Adding upstream version 18.2.2.upstream/18.2.2

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

19 files changed, 4430 insertions, 0 deletions

diff --git a/src/spdk/test/app/fuzz/Makefile b/src/spdk/test/app/fuzz/Makefile
new file mode 100644
index 000000000..1f0a81b92
--- /dev/null
+++ b/src/spdk/test/app/fuzz/Makefile
@@ -0,0 +1,48 @@
+#
+#  BSD LICENSE
+#
+#  Copyright (c) Intel Corporation.
+#  All rights reserved.
+#
+#  Redistribution and use in source and binary forms, with or without
+#  modification, are permitted provided that the following conditions
+#  are met:
+#
+#    * Redistributions of source code must retain the above copyright
+#      notice, this list of conditions and the following disclaimer.
+#    * Redistributions in binary form must reproduce the above copyright
+#      notice, this list of conditions and the following disclaimer in
+#      the documentation and/or other materials provided with the
+#      distribution.
+#    * Neither the name of Intel Corporation nor the names of its
+#      contributors may be used to endorse or promote products derived
+#      from this software without specific prior written permission.
+#
+#  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+#  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+#  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+#  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+#  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+#  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+#  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+#  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+#  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+#  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+#  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#
+
+SPDK_ROOT_DIR := $(abspath $(CURDIR)/../../..)
+include $(SPDK_ROOT_DIR)/mk/spdk.common.mk
+
+DIRS-y += nvme_fuzz
+DIRS-y += iscsi_fuzz
+
+ifeq ($(OS),Linux)
+DIRS-$(CONFIG_VIRTIO) += vhost_fuzz
+endif
+.PHONY: all clean $(DIRS-y)
+
+all: $(DIRS-y)
+clean: $(DIRS-y)
+
+include $(SPDK_ROOT_DIR)/mk/spdk.subdirs.mk
diff --git a/src/spdk/test/app/fuzz/common/fuzz_common.h b/src/spdk/test/app/fuzz/common/fuzz_common.h
new file mode 100644
index 000000000..7619f4fb1
--- /dev/null
+++ b/src/spdk/test/app/fuzz/common/fuzz_common.h
@@ -0,0 +1,303 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright (c) Intel Corporation.
+ *   All rights reserved.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following conditions
+ *   are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in
+ *       the documentation and/or other materials provided with the
+ *       distribution.
+ *     * Neither the name of Intel Corporation nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "spdk/stdinc.h"
+#include "spdk/env.h"
+#include "spdk/file.h"
+#include "spdk/base64.h"
+#include "spdk/json.h"
+
+#define DEFAULT_RUNTIME 30 /* seconds */
+#define MAX_RUNTIME_S 86400 /* 24 hours */
+#define IO_TIMEOUT_S 5
+
+#define UNSIGNED_2BIT_MAX ((1 << 2) - 1)
+#define UNSIGNED_4BIT_MAX ((1 << 4) - 1)
+#define UNSIGNED_8BIT_MAX ((1 << 8) - 1)
+
+typedef bool (*json_parse_fn)(void *ele, struct spdk_json_val *val, size_t num_vals);
+
+static void
+fuzz_fill_random_bytes(char *character_repr, size_t len, unsigned int *rand_seed)
+{
+	size_t i;
+
+	for (i = 0; i < len; i++) {
+		character_repr[i] = rand_r(rand_seed) % UINT8_MAX;
+	}
+}
+
+static uint64_t
+fuzz_refresh_timeout(void)
+{
+	uint64_t current_ticks;
+	uint64_t new_timeout_ticks;
+
+	current_ticks = spdk_get_ticks();
+
+	new_timeout_ticks = current_ticks + IO_TIMEOUT_S * spdk_get_ticks_hz();
+	assert(new_timeout_ticks > current_ticks);
+
+	return new_timeout_ticks;
+}
+
+static char *
+fuzz_get_value_base_64_buffer(void *item, size_t len)
+{
+	char *value_string;
+	size_t total_size;
+	int rc;
+
+	/* Null pointer */
+	total_size = spdk_base64_get_encoded_strlen(len) + 1;
+
+	value_string = calloc(1, total_size);
+	if (value_string == NULL) {
+		return NULL;
+	}
+
+	rc = spdk_base64_encode(value_string, item, len);
+	if (rc < 0) {
+		free(value_string);
+		return NULL;
+	}
+
+	return value_string;
+}
+
+static int
+fuzz_get_base_64_buffer_value(void *item, size_t len, char *buf, size_t buf_len)
+{
+	size_t size_of_data;
+	char *new_buf;
+	int rc;
+
+	new_buf = malloc(buf_len + 1);
+	if (new_buf == NULL) {
+		return -ENOMEM;
+	}
+
+	snprintf(new_buf, buf_len + 1, "%s", buf);
+
+	size_of_data = spdk_base64_get_decoded_len(buf_len);
+
+	if (size_of_data < len) {
+		free(new_buf);
+		return -EINVAL;
+	}
+
+	rc = spdk_base64_decode(item, &size_of_data, new_buf);
+
+	if (rc || size_of_data != len) {
+		free(new_buf);
+		return -EINVAL;
+	}
+
+	free(new_buf);
+	return 0;
+}
+
+static ssize_t
+read_json_into_buffer(const char *filename, struct spdk_json_val **values, void **file_data)
+{
+	FILE *file = fopen(filename, "r");
+	size_t file_data_size;
+	ssize_t num_json_values = 0, rc;
+
+	if (file == NULL) {
+		/* errno is set by fopen */
+		return 0;
+	}
+
+	*file_data = spdk_posix_file_load(file, &file_data_size);
+	if (*file_data == NULL) {
+		fclose(file);
+		return 0;
+	}
+
+	fclose(file);
+
+	num_json_values = spdk_json_parse(*file_data, file_data_size, NULL, 0, NULL,
+					  SPDK_JSON_PARSE_FLAG_ALLOW_COMMENTS);
+
+	*values = calloc(num_json_values, sizeof(**values));
+	if (values == NULL) {
+		free(*file_data);
+		*file_data = NULL;
+		return 0;
+	}
+
+	rc = spdk_json_parse(*file_data, file_data_size, *values, num_json_values, NULL,
+			     SPDK_JSON_PARSE_FLAG_ALLOW_COMMENTS);
+	if (num_json_values != rc) {
+		free(*values);
+		*values = NULL;
+		free(*file_data);
+		*file_data = NULL;
+		return 0;
+	}
+
+	return num_json_values;
+}
+
+static size_t
+double_arr_size(void **buffer, size_t num_ele, size_t ele_size)
+{
+	void *tmp;
+	size_t new_num_ele, allocation_size;
+
+	if (num_ele > SIZE_MAX / 2) {
+		return 0;
+	}
+
+	new_num_ele = num_ele * 2;
+
+	if (new_num_ele > SIZE_MAX / ele_size) {
+		return 0;
+	}
+
+	allocation_size = new_num_ele * ele_size;
+
+	tmp = realloc(*buffer, allocation_size);
+	if (tmp != NULL) {
+		*buffer = tmp;
+		return new_num_ele;
+	}
+
+	return 0;
+}
+
+static uint64_t
+fuzz_parse_args_into_array(const char *file, void **arr, size_t ele_size, const char *obj_name,
+			   json_parse_fn cb_fn)
+{
+	ssize_t i, num_json_values;
+	struct spdk_json_val *values = NULL, *values_head = NULL, *obj_start;
+	void *file_data = NULL;;
+	char *arr_idx_pointer;
+	size_t num_arr_elements, arr_elements_used, values_in_obj;
+	bool rc;
+
+	num_json_values = read_json_into_buffer(file, &values_head, &file_data);
+	values = values_head;
+	if (num_json_values == 0 || values == NULL) {
+		if (file_data != NULL) {
+			free(file_data);
+		}
+		fprintf(stderr, "The file provided does not exist or we were unable to parse it.\n");
+		return 0;
+	}
+
+	num_arr_elements = 10;
+	arr_elements_used = 0;
+	*arr = calloc(num_arr_elements, ele_size);
+	arr_idx_pointer = (char *)*arr;
+	if (arr_idx_pointer == NULL) {
+		free(values);
+		free(file_data);
+		return 0;
+	}
+
+	i = 0;
+	while (i < num_json_values) {
+		if (values->type != SPDK_JSON_VAL_NAME) {
+			i++;
+			values++;
+			continue;
+		}
+
+		if (!strncmp(values->start, obj_name, values->len)) {
+			i++;
+			values++;
+			assert(values->type == SPDK_JSON_VAL_OBJECT_BEGIN);
+			obj_start = values;
+			values_in_obj = spdk_json_val_len(obj_start);
+			values += values_in_obj;
+			i += values_in_obj;
+
+			rc = cb_fn((void *)arr_idx_pointer, obj_start, values_in_obj);
+			if (rc == false) {
+				fprintf(stderr, "failed to parse file after %lu elements.\n", arr_elements_used);
+				goto fail;
+			}
+
+			arr_idx_pointer += ele_size;
+			arr_elements_used++;
+			if (arr_elements_used == num_arr_elements) {
+				num_arr_elements = double_arr_size(arr, num_arr_elements, ele_size);
+				if (num_arr_elements == 0) {
+					fprintf(stderr, "failed to allocate enough space for all json elements in your file.\n");
+					goto fail;
+				} else {
+					/* reset the array element position in case the pointer changed. */
+					arr_idx_pointer = ((char *)*arr) + arr_elements_used * ele_size;
+				}
+			}
+
+			continue;
+		} else {
+			i++;
+			values++;
+			continue;
+		}
+	}
+
+	if (arr_elements_used == 0) {
+		goto fail;
+	}
+
+	free(values_head);
+	free(file_data);
+	return arr_elements_used;
+fail:
+	free(values_head);
+	free(file_data);
+	free(*arr);
+	*arr = NULL;
+	return 0;
+}
+
+static int
+fuzz_parse_json_num(struct spdk_json_val *val, uint64_t max_val, uint64_t *val_ptr)
+{
+	uint64_t tmp_val;
+	int rc;
+
+	rc = spdk_json_number_to_uint64(val, &tmp_val);
+	if (rc || tmp_val > max_val) {
+		return -EINVAL;
+	} else {
+		*val_ptr = tmp_val;
+		return 0;
+	}
+}
diff --git a/src/spdk/test/app/fuzz/common/fuzz_rpc.py b/src/spdk/test/app/fuzz/common/fuzz_rpc.py
new file mode 100755
index 000000000..05cb67ed8
--- /dev/null
+++ b/src/spdk/test/app/fuzz/common/fuzz_rpc.py
@@ -0,0 +1,106 @@
+#!/usr/bin/env python3
+
+from rpc.client import print_dict, JSONRPCException
+
+import logging
+import argparse
+import rpc
+import sys
+import shlex
+
+try:
+    from shlex import quote
+except ImportError:
+    from pipes import quote
+
+
+def print_array(a):
+    print(" ".join((quote(v) for v in a)))
+
+
+def _fuzz_vhost_create_dev(client, socket, is_blk, use_bogus_buffer, use_valid_buffer, test_scsi_tmf, valid_lun):
+    """Create a new device in the vhost fuzzer.
+
+    Args:
+        socket: A valid unix domain socket for the dev to bind to.
+        is_blk: if set, create a virtio_blk device, otherwise use scsi.
+        use_bogus_buffer: if set, pass an invalid memory address as a buffer accompanying requests.
+        use_valid_buffer: if set, pass in a valid memory buffer with requests. Overrides use_bogus_buffer.
+        test_scsi_tmf: Test scsi management commands on the given device. Valid if and only if is_blk is false.
+        valid_lun: Supply only a valid lun number when submitting commands to the given device. Valid if and only if is_blk is false.
+
+    Returns:
+        True or False
+    """
+
+    params = {"socket": socket,
+              "is_blk": is_blk,
+              "use_bogus_buffer": use_bogus_buffer,
+              "use_valid_buffer": use_valid_buffer,
+              "test_scsi_tmf": test_scsi_tmf,
+              "valid_lun": valid_lun}
+
+    return client.call("fuzz_vhost_create_dev", params)
+
+
+if __name__ == "__main__":
+    parser = argparse.ArgumentParser(
+        description='SPDK RPC command line interface. NOTE: spdk/scripts/ is expected in PYTHONPATH')
+    parser.add_argument('-s', dest='server_addr',
+                        help='RPC domain socket path or IP address', default='/var/tmp/spdk.sock')
+    parser.add_argument('-p', dest='port',
+                        help='RPC port number (if server_addr is IP address)',
+                        default=5260, type=int)
+    parser.add_argument('-t', dest='timeout',
+                        help='Timeout as a floating point number expressed in seconds waiting for response. Default: 60.0',
+                        default=60.0, type=float)
+    parser.add_argument('-v', dest='verbose', action='store_const', const="INFO",
+                        help='Set verbose mode to INFO', default="ERROR")
+    parser.add_argument('--verbose', dest='verbose', choices=['DEBUG', 'INFO', 'ERROR'],
+                        help="""Set verbose level. """)
+    subparsers = parser.add_subparsers(help='RPC methods')
+
+    def fuzz_vhost_create_dev(args):
+        _fuzz_vhost_create_dev(
+            args.client,
+            args.socket,
+            args.is_blk,
+            args.use_bogus_buffer,
+            args.use_valid_buffer,
+            args.test_scsi_tmf,
+            args.valid_lun)
+
+    p = subparsers.add_parser('fuzz_vhost_create_dev', help="Add a new device to the vhost fuzzer.")
+    p.add_argument('-s', '--socket', help="Path to a valid unix domain socket for dev binding.")
+    p.add_argument('-b', '--is-blk', help='The specified socket corresponds to a vhost-blk dev.', action='store_true')
+    p.add_argument('-u', '--use-bogus-buffer', help='Pass bogus buffer addresses with requests when fuzzing.', action='store_true')
+    p.add_argument('-v', '--use-valid-buffer', help='Pass valid buffers when fuzzing. overrides use-bogus-buffer.', action='store_true')
+    p.add_argument('-m', '--test-scsi-tmf', help='for a scsi device, test scsi management commands.', action='store_true')
+    p.add_argument('-l', '--valid-lun', help='for a scsi device, test only using valid lun IDs.', action='store_true')
+    p.set_defaults(func=fuzz_vhost_create_dev)
+
+    def call_rpc_func(args):
+        try:
+            args.func(args)
+        except JSONRPCException as ex:
+            print(ex.message)
+            exit(1)
+
+    def execute_script(parser, client, fd):
+        for rpc_call in map(str.rstrip, fd):
+            if not rpc_call.strip():
+                continue
+            args = parser.parse_args(shlex.split(rpc_call))
+            args.client = client
+            call_rpc_func(args)
+
+    args = parser.parse_args()
+    args.client = rpc.client.JSONRPCClient(args.server_addr, args.port, args.timeout, log_level=getattr(logging, args.verbose.upper()))
+    if hasattr(args, 'func'):
+        call_rpc_func(args)
+    elif sys.stdin.isatty():
+        # No arguments and no data piped through stdin
+        parser.print_help()
+        exit(1)
+    else:
+        execute_script(parser, args.client, sys.stdin)
diff --git a/src/spdk/test/app/fuzz/iscsi_fuzz/.gitignore b/src/spdk/test/app/fuzz/iscsi_fuzz/.gitignore
new file mode 100644
index 000000000..3982bd220
--- /dev/null
+++ b/src/spdk/test/app/fuzz/iscsi_fuzz/.gitignore
@@ -0,0 +1 @@
+iscsi_fuzz
diff --git a/src/spdk/test/app/fuzz/iscsi_fuzz/Makefile b/src/spdk/test/app/fuzz/iscsi_fuzz/Makefile
new file mode 100644
index 000000000..0131e089a
--- /dev/null
+++ b/src/spdk/test/app/fuzz/iscsi_fuzz/Makefile
@@ -0,0 +1,51 @@
+#
+#  Copyright (c) Intel Corporation.
+#  All rights reserved.
+#
+#  Redistribution and use in source and binary forms, with or without
+#  modification, are permitted provided that the following conditions
+#  are met:
+#
+#    * Redistributions of source code must retain the above copyright
+#      notice, this list of conditions and the following disclaimer.
+#    * Redistributions in binary form must reproduce the above copyright
+#      notice, this list of conditions and the following disclaimer in
+#      the documentation and/or other materials provided with the
+#      distribution.
+#    * Neither the name of Intel Corporation nor the names of its
+#      contributors may be used to endorse or promote products derived
+#      from this software without specific prior written permission.
+#
+#  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+#  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+#  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+#  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+#  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+#  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+#  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+#  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+#  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+#  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+#  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#
+
+SPDK_ROOT_DIR := $(abspath $(CURDIR)/../../../..)
+include $(SPDK_ROOT_DIR)/mk/spdk.common.mk
+include $(SPDK_ROOT_DIR)/mk/spdk.modules.mk
+
+APP = iscsi_fuzz
+
+CFLAGS += -I$(SPDK_ROOT_DIR)/lib
+CFLAGS += -I$(SPDK_ROOT_DIR)/include
+
+C_SRCS := iscsi_fuzz.c
+
+ISCSI_OBJS = md5 param conn tgt_node init_grp portal_grp
+
+LIBS += $(SCSI_OBJS:%=$(SPDK_ROOT_DIR)/lib/scsi/%.o)
+LIBS += $(ISCSI_OBJS:%=$(SPDK_ROOT_DIR)/lib/iscsi/%.o)
+
+SPDK_LIB_LIST += $(SOCK_MODULES_LIST)
+SPDK_LIB_LIST += conf event json jsonrpc log scsi bdev notify rpc sock thread trace util
+
+include $(SPDK_ROOT_DIR)/mk/spdk.app.mk
diff --git a/src/spdk/test/app/fuzz/iscsi_fuzz/README.md b/src/spdk/test/app/fuzz/iscsi_fuzz/README.md
new file mode 100644
index 000000000..c9ef02e6a
--- /dev/null
+++ b/src/spdk/test/app/fuzz/iscsi_fuzz/README.md
@@ -0,0 +1,27 @@
+# Overview
+
+This application is intended to fuzz test the iSCSI target by submitting
+randomized PDU commands through a simulated iSCSI initiator.
+
+# Input
+
+1. iSCSI initiator send a login request PDU to iSCSI Target. Once a session is connected,
+2. iSCSI initiator send huge amount and random PDUs continuously to iSCSI Target.
+3. iSCSI initiator send a logout request PDU to iSCSI Target in the end.
+Especially, iSCSI initiator need to build different bhs according to different bhs opcode.
+Then iSCSI initiator will receive all kinds of responsed opcodes from iSCSI Target.
+The application will terminate when run time expires (see the -t flag).
+
+# Output
+
+By default, the fuzzer will print commands that:
+1. Complete successfully back from the target, or
+2. Are outstanding at the time of a connection error occurs.
+Commands are dumped as named objects in json format which can then be supplied back to the
+script for targeted debugging on a subsequent run.
+
+At the end of each test run, a summary is printed in the following format:
+
+~~~
+device 0x11c3b90 stats: Sent 1543 valid opcode PDUs, 16215 invalid opcode PDUs.
+~~~
diff --git a/src/spdk/test/app/fuzz/iscsi_fuzz/iscsi_fuzz.c b/src/spdk/test/app/fuzz/iscsi_fuzz/iscsi_fuzz.c
new file mode 100644
index 000000000..359b95981
--- /dev/null
+++ b/src/spdk/test/app/fuzz/iscsi_fuzz/iscsi_fuzz.c
@@ -0,0 +1,1092 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright (c) Intel Corporation.
+ *   All rights reserved.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following conditions
+ *   are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in
+ *       the documentation and/or other materials provided with the
+ *       distribution.
+ *     * Neither the name of Intel Corporation nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "spdk/stdinc.h"
+#include "spdk/conf.h"
+#include "spdk/event.h"
+#include "spdk/util.h"
+#include "spdk/string.h"
+#include "spdk/likely.h"
+#include "spdk/json.h"
+#include "spdk/endian.h"
+#include "spdk/bdev.h"
+#include "spdk/notify.h"
+#include "spdk/scsi.h"
+#include "spdk_internal/mock.h"
+#include "spdk/scsi_spec.h"
+#include "iscsi/conn.h"
+#include "iscsi/iscsi.c"
+#include "scsi/scsi_internal.h"
+#include "spdk/sock.h"
+
+#define GET_PDU_LOOP_COUNT	16
+#define DEFAULT_RUNTIME		30	/* seconds */
+#define MAX_RUNTIME_S		86400	/* 24 hours */
+
+/* Global run state */
+uint64_t		g_runtime_ticks;
+int			g_runtime;
+int			g_num_active_threads;
+bool			g_run = true;
+bool			g_is_valid_opcode = true;
+
+struct spdk_log_flag SPDK_LOG_ISCSI = {
+	.name = "iscsi",
+	.enabled = false,
+};
+
+/* Global resources */
+TAILQ_HEAD(, spdk_iscsi_pdu)		g_get_pdu_list;
+TAILQ_HEAD(, fuzz_iscsi_dev_ctx)	g_dev_list = TAILQ_HEAD_INITIALIZER(g_dev_list);
+struct spdk_poller			*g_app_completion_poller;
+void					*g_valid_buffer;
+unsigned int				g_random_seed;
+char					*g_tgt_ip = "127.0.0.1";
+char					*g_tgt_port = "3260";
+/* TBD: Discovery login to get target information. We use fixed IQN for target for now. */
+char					*g_tgt_name = "iqn.2016-06.io.spdk:disk1";
+char					*g_init_name = "iqn.2016-06.io.spdk:fuzzinit";
+
+struct fuzz_iscsi_iov_ctx {
+	struct iovec			iov_req;
+	struct iovec			iov_data;
+	struct iovec			iov_resp;
+};
+
+struct fuzz_iscsi_io_ctx {
+	struct fuzz_iscsi_iov_ctx		iov_ctx;
+	union {
+		struct iscsi_bhs		*bhs;
+		struct iscsi_bhs_nop_out	*nop_out_req;
+		struct iscsi_bhs_scsi_req	*scsi_req;
+		struct iscsi_bhs_task_req	*task_req;
+		struct iscsi_bhs_login_req	*login_req;
+		struct iscsi_bhs_text_req	*text_req;
+		struct iscsi_bhs_data_out	*data_out_req;
+		struct iscsi_bhs_logout_req	*logout_req;
+		struct iscsi_bhs_snack_req	*snack_req;
+	} req;
+};
+
+struct fuzz_iscsi_dev_ctx {
+	struct spdk_iscsi_sess			sess;
+	struct spdk_iscsi_conn			*conn;
+	struct fuzz_iscsi_io_ctx		io_ctx;
+
+	struct spdk_thread			*thread;
+	struct spdk_poller			*poller;
+	unsigned int				random_seed, current_cmd_sn;
+	uint64_t				num_sent_pdus;
+	uint64_t				num_valid_pdus;
+
+	TAILQ_ENTRY(fuzz_iscsi_dev_ctx)		link;
+};
+
+static void
+fuzz_fill_random_bytes(char *character_repr, size_t len, unsigned int *rand_seed)
+{
+	size_t i;
+
+	for (i = 0; i < len; i++) {
+		character_repr[i] = rand_r(rand_seed) % UINT8_MAX;
+	}
+}
+
+static char *
+fuzz_get_value_base_64_buffer(void *item, size_t len)
+{
+	char *value_string;
+	size_t total_size;
+	int rc;
+
+	/* Null pointer */
+	total_size = spdk_base64_get_encoded_strlen(len) + 1;
+
+	value_string = calloc(1, total_size);
+	if (value_string == NULL) {
+		return NULL;
+	}
+
+	rc = spdk_base64_encode(value_string, item, len);
+	if (rc < 0) {
+		free(value_string);
+		return NULL;
+	}
+
+	return value_string;
+}
+
+int
+iscsi_chap_get_authinfo(struct iscsi_chap_auth *auth, const char *authuser,
+			int ag_tag)
+{
+	return 0;
+}
+
+void
+shutdown_iscsi_conns_done(void)
+{
+	return;
+}
+
+void
+iscsi_put_pdu(struct spdk_iscsi_pdu *pdu)
+{
+	if (!pdu) {
+		return;
+	}
+
+	pdu->ref--;
+	if (pdu->ref < 0) {
+		pdu->ref = 0;
+	}
+
+	if (pdu->ref == 0) {
+		if (pdu->data) {
+			free(pdu->data);
+		}
+		free(pdu);
+	}
+}
+
+struct spdk_iscsi_pdu *
+iscsi_get_pdu(struct spdk_iscsi_conn *conn)
+{
+	struct spdk_iscsi_pdu *pdu;
+
+	pdu = calloc(1, sizeof(*pdu));
+	if (!pdu) {
+		return NULL;
+	}
+
+	pdu->ref = 1;
+	pdu->conn = conn;
+
+	return pdu;
+}
+
+static void
+iscsi_task_free(struct spdk_scsi_task *scsi_task)
+{
+	struct spdk_iscsi_task *task = iscsi_task_from_scsi_task(scsi_task);
+
+	assert(task->parent == NULL);
+
+	iscsi_task_disassociate_pdu(task);
+	assert(task->conn->pending_task_cnt > 0);
+	task->conn->pending_task_cnt--;
+	free(task);
+}
+
+struct spdk_iscsi_task *
+iscsi_task_get(struct spdk_iscsi_conn *conn, struct spdk_iscsi_task *parent,
+	       spdk_scsi_task_cpl cpl_fn)
+{
+	struct spdk_iscsi_task *task;
+
+	/* iSCSI subtask is not necessary for now. */
+	assert(parent == NULL);
+
+	task = calloc(1, sizeof(*task));
+	if (!task) {
+		printf("Unable to get task\n");
+		abort();
+	}
+
+	task->conn = conn;
+	assert(conn->pending_task_cnt < UINT32_MAX);
+	conn->pending_task_cnt++;
+	spdk_scsi_task_construct(&task->scsi, cpl_fn, iscsi_task_free);
+
+	return task;
+}
+
+static void
+cleanup(void)
+{
+	struct fuzz_iscsi_dev_ctx *dev_ctx, *tmp;
+
+	TAILQ_FOREACH_SAFE(dev_ctx, &g_dev_list, link, tmp) {
+		printf("device %p stats: Sent %lu valid opcode PDUs, %lu invalid opcode PDUs.\n",
+		       dev_ctx, dev_ctx->num_valid_pdus,
+		       dev_ctx->num_sent_pdus - dev_ctx->num_valid_pdus);
+		free(dev_ctx);
+	}
+
+	spdk_free(g_valid_buffer);
+}
+
+/* data dumping functions begin */
+static int
+dump_iscsi_cmd(void *ctx, const void *data, size_t size)
+{
+	fprintf(stderr, "%s\n", (const char *)data);
+	return 0;
+}
+
+static void
+print_scsi_io_data(struct spdk_json_write_ctx *w, struct fuzz_iscsi_io_ctx *io_ctx)
+{
+	char *data_segment_len;
+
+	data_segment_len = fuzz_get_value_base_64_buffer((void *)io_ctx->req.bhs->data_segment_len,
+			   sizeof(io_ctx->req.bhs->data_segment_len));
+
+	spdk_json_write_named_uint32(w, "opcode", io_ctx->req.bhs->opcode);
+	spdk_json_write_named_uint32(w, "immediate", io_ctx->req.bhs->immediate);
+	spdk_json_write_named_uint32(w, "reserved", io_ctx->req.bhs->reserved);
+	spdk_json_write_named_uint32(w, "total_ahs_len", io_ctx->req.bhs->total_ahs_len);
+	spdk_json_write_named_string(w, "data_segment_len", data_segment_len);
+	spdk_json_write_named_uint32(w, "itt", io_ctx->req.bhs->itt);
+	spdk_json_write_named_uint32(w, "exp_stat_sn", io_ctx->req.bhs->exp_stat_sn);
+
+	free(data_segment_len);
+}
+
+static void
+print_req_obj(struct fuzz_iscsi_dev_ctx *dev_ctx, struct fuzz_iscsi_io_ctx *io_ctx)
+{
+	struct spdk_json_write_ctx *w;
+
+	w = spdk_json_write_begin(dump_iscsi_cmd, NULL, SPDK_JSON_WRITE_FLAG_FORMATTED);
+	spdk_json_write_named_object_begin(w, "bhs");
+	print_scsi_io_data(w, io_ctx);
+	spdk_json_write_object_end(w);
+	spdk_json_write_end(w);
+}
+
+/* data dumping functions end */
+
+/* dev initialization begin */
+static int
+fuzz_iscsi_dev_init(void)
+{
+	struct fuzz_iscsi_dev_ctx *dev_ctx;
+	int rc = 0;
+
+	dev_ctx = calloc(1, sizeof(*dev_ctx));
+	if (dev_ctx == NULL) {
+		return -ENOMEM;
+	}
+
+	dev_ctx->thread = spdk_get_thread();
+	if (dev_ctx->thread == NULL) {
+		fprintf(stderr, "Unable to get a thread for a fuzz device.\n");
+		rc = -EINVAL;
+		goto error_out;
+	}
+
+	dev_ctx->current_cmd_sn = 0;
+
+	TAILQ_INSERT_TAIL(&g_dev_list, dev_ctx, link);
+	return 0;
+
+error_out:
+	free(dev_ctx);
+	return rc;
+}
+/* dev initialization end */
+
+/* build requests begin */
+static void
+prep_iscsi_pdu_bhs_opcode_cmd(struct fuzz_iscsi_dev_ctx *dev_ctx, struct fuzz_iscsi_io_ctx *io_ctx)
+{
+	io_ctx->iov_ctx.iov_req.iov_len = sizeof(struct iscsi_bhs);
+	fuzz_fill_random_bytes((char *)io_ctx->req.bhs, sizeof(struct iscsi_bhs),
+			       &dev_ctx->random_seed);
+}
+/* build requests end */
+
+static int
+iscsi_pdu_hdr_op_login_rsp(struct spdk_iscsi_conn *conn, struct spdk_iscsi_pdu *pdu)
+{
+	return 0;
+}
+
+static int
+iscsi_fuzz_pdu_hdr_handle(struct spdk_iscsi_conn *conn, struct spdk_iscsi_pdu *pdu)
+{
+	int opcode;
+	int rc = 0;
+
+	opcode = pdu->bhs.opcode;
+	if (opcode == ISCSI_OP_LOGIN_RSP) {
+		return iscsi_pdu_hdr_op_login_rsp(conn, pdu);
+	}
+
+	switch (opcode) {
+	case ISCSI_OP_LOGOUT_RSP:
+		fprintf(stderr, "Received logout hdr_handle response opcode(0x26) from Target.\n");
+		conn->is_logged_out = true;
+		break;
+	case ISCSI_OP_NOPIN:
+	case ISCSI_OP_SCSI_RSP:
+	case ISCSI_OP_TASK_RSP:
+	case ISCSI_OP_TEXT_RSP:
+	case ISCSI_OP_SCSI_DATAIN:
+	case ISCSI_OP_R2T:
+	case ISCSI_OP_ASYNC:
+	case ISCSI_OP_VENDOR_3C:
+	case ISCSI_OP_VENDOR_3D:
+	case ISCSI_OP_VENDOR_3E:
+		fprintf(stderr, "Received hdr_handle response opcode from Target is 0x%x.\n", pdu->bhs.opcode);
+		break;
+	case ISCSI_OP_REJECT:
+		fprintf(stderr, "Received rejected hdr_handle response opcode(0x3f) from Target.\n");
+		break;
+	default:
+		rc = -1;
+		break;
+	}
+
+	return rc;
+}
+
+static int
+iscsi_pdu_payload_op_login_rsp(struct spdk_iscsi_conn *conn, struct spdk_iscsi_pdu *pdu)
+{
+	struct iscsi_bhs_login_rsp *rsph;
+
+	rsph = (struct iscsi_bhs_login_rsp *)&pdu->bhs;
+	if (rsph == NULL) {
+		return -1;
+	}
+
+	assert(rsph->tsih != 0);
+	assert(rsph->status_class == 0);
+	assert(ISCSI_BHS_LOGIN_GET_TBIT(rsph->flags));
+	assert(!(rsph->flags & ISCSI_LOGIN_CONTINUE));
+	assert((rsph->flags & ISCSI_LOGIN_NEXT_STAGE_MASK) == ISCSI_LOGIN_NEXT_STAGE_3);
+
+	/* We got the Login Final Response and move to Full-Feature Phase. */
+	conn->full_feature = 1;
+	return 0;
+}
+
+static int
+iscsi_fuzz_pdu_payload_handle(struct spdk_iscsi_conn *conn, struct spdk_iscsi_pdu *pdu)
+{
+	int opcode;
+	int rc = 0;
+
+	opcode = pdu->bhs.opcode;
+	fprintf(stderr, "Received payload_handle response opcode from Target is 0x%x.\n", opcode);
+
+	switch (opcode) {
+	case ISCSI_OP_LOGIN_RSP:
+		rc = iscsi_pdu_payload_op_login_rsp(conn, pdu);
+		break;
+	case ISCSI_OP_NOPIN:
+	case ISCSI_OP_SCSI_RSP:
+	case ISCSI_OP_TASK_RSP:
+	case ISCSI_OP_TEXT_RSP:
+	case ISCSI_OP_SCSI_DATAIN:
+	case ISCSI_OP_R2T:
+	case ISCSI_OP_ASYNC:
+	case ISCSI_OP_VENDOR_3C:
+	case ISCSI_OP_VENDOR_3D:
+	case ISCSI_OP_VENDOR_3E:
+	case ISCSI_OP_REJECT:
+		break;
+	default:
+		rc = -1;
+		break;
+	}
+
+	return rc;
+}
+
+static int
+iscsi_fuzz_read_pdu(struct spdk_iscsi_conn *conn)
+{
+	enum iscsi_pdu_recv_state prev_state;
+	struct spdk_iscsi_pdu *pdu;
+	uint32_t data_len;
+	int rc;
+
+	do {
+		prev_state = conn->pdu_recv_state;
+		pdu = conn->pdu_in_progress;
+
+		switch (conn->pdu_recv_state) {
+		case ISCSI_PDU_RECV_STATE_AWAIT_PDU_READY:
+			assert(conn->pdu_in_progress == NULL);
+
+			conn->pdu_in_progress = iscsi_get_pdu(conn);
+			if (conn->pdu_in_progress == NULL) {
+				return SPDK_ISCSI_CONNECTION_FATAL;
+			}
+			TAILQ_INSERT_TAIL(&g_get_pdu_list, conn->pdu_in_progress, tailq);
+			conn->pdu_recv_state = ISCSI_PDU_RECV_STATE_AWAIT_PDU_HDR;
+			break;
+		case ISCSI_PDU_RECV_STATE_AWAIT_PDU_HDR:
+			if (pdu->bhs_valid_bytes < ISCSI_BHS_LEN) {
+				rc = iscsi_conn_read_data(conn,
+							  ISCSI_BHS_LEN - pdu->bhs_valid_bytes,
+							  (uint8_t *)&pdu->bhs + pdu->bhs_valid_bytes);
+				if (rc < 0) {
+					conn->pdu_recv_state = ISCSI_PDU_RECV_STATE_ERROR;
+					break;
+				}
+				pdu->bhs_valid_bytes += rc;
+				if (pdu->bhs_valid_bytes < ISCSI_BHS_LEN) {
+					return 0;
+				}
+			}
+
+			pdu->data_segment_len = ISCSI_ALIGN(DGET24(pdu->bhs.data_segment_len));
+
+			rc = iscsi_fuzz_pdu_hdr_handle(conn, pdu);
+			if (rc < 0) {
+				printf("Critical error is detected. Close the connection\n");
+				conn->pdu_recv_state = ISCSI_PDU_RECV_STATE_ERROR;
+				break;
+			}
+
+			if (conn->is_logged_out) {
+				printf("pdu received after logout\n");
+				conn->pdu_recv_state = ISCSI_PDU_RECV_STATE_ERROR;
+				break;
+			}
+
+			conn->pdu_recv_state = ISCSI_PDU_RECV_STATE_AWAIT_PDU_PAYLOAD;
+			break;
+		case ISCSI_PDU_RECV_STATE_AWAIT_PDU_PAYLOAD:
+			data_len = pdu->data_segment_len;
+			if (data_len != 0 && pdu->data_buf == NULL) {
+				pdu->data_buf = calloc(1, data_len);
+				if (pdu->data_buf == NULL) {
+					return 0;
+				}
+				pdu->data = pdu->data_buf;
+			}
+
+			/* copy the actual data into local buffer */
+			if (pdu->data_valid_bytes < data_len) {
+				rc = iscsi_conn_read_data_segment(conn, pdu, data_len);
+				if (rc < 0) {
+					conn->pdu_recv_state = ISCSI_PDU_RECV_STATE_ERROR;
+					break;
+				}
+				pdu->data_valid_bytes += rc;
+				if (pdu->data_valid_bytes < data_len) {
+					return 0;
+				}
+			}
+
+			/* All data for this PDU has now been read from the socket. */
+			spdk_trace_record(TRACE_ISCSI_READ_PDU, conn->id, pdu->data_valid_bytes,
+					  (uintptr_t)pdu, pdu->bhs.opcode);
+
+			if (!pdu->is_rejected) {
+				rc = iscsi_fuzz_pdu_payload_handle(conn, pdu);
+			} else {
+				rc = 0;
+			}
+			if (rc == 0) {
+				spdk_trace_record(TRACE_ISCSI_TASK_EXECUTED, 0, 0, (uintptr_t)pdu, 0);
+				conn->pdu_in_progress = NULL;
+				conn->pdu_recv_state = ISCSI_PDU_RECV_STATE_AWAIT_PDU_READY;
+				return 1;
+			} else {
+				conn->pdu_recv_state = ISCSI_PDU_RECV_STATE_ERROR;
+			}
+			break;
+		case ISCSI_PDU_RECV_STATE_ERROR:
+			return SPDK_ISCSI_CONNECTION_FATAL;
+		default:
+			assert(false);
+			printf("code should not come here\n");
+			break;
+		}
+	} while (prev_state != conn->pdu_recv_state);
+
+	return 0;
+}
+
+#define GET_PDU_LOOP_COUNT	16
+
+static int
+fuzz_iscsi_handle_incoming_pdus(struct spdk_iscsi_conn *conn)
+{
+	int i, rc;
+
+	/* Read new PDUs from network */
+	for (i = 0; i < GET_PDU_LOOP_COUNT; i++) {
+		rc = iscsi_fuzz_read_pdu(conn);
+		if (rc == 0) {
+			break;
+		} else if (rc < 0) {
+			return rc;
+		}
+	}
+
+	return i;
+}
+
+static void
+fuzz_iscsi_send_login_request(struct fuzz_iscsi_dev_ctx *dev_ctx, uint8_t session_type)
+{
+	struct fuzz_iscsi_io_ctx *io_ctx = NULL;
+	struct spdk_iscsi_pdu *req_pdu;
+	struct iscsi_bhs_login_req *login_req;
+	struct spdk_iscsi_conn *conn = dev_ctx->conn;
+
+	req_pdu = iscsi_get_pdu(conn);
+	req_pdu->writev_offset = 0;
+	req_pdu->hdigest_valid_bytes = 0;
+	req_pdu->ahs_valid_bytes = 0;
+	req_pdu->data_buf_len = 8192;
+	req_pdu->data = calloc(1, 8192);
+	assert(req_pdu->data != NULL);
+	req_pdu->data_segment_len = 0;
+
+	login_req = (struct iscsi_bhs_login_req *)&req_pdu->bhs;
+	io_ctx = &dev_ctx->io_ctx;
+	io_ctx->req.login_req = login_req;
+	io_ctx->req.login_req->version_min = 0;
+	/* a new session */
+	io_ctx->req.login_req->tsih = 0;
+
+	req_pdu->bhs.opcode = ISCSI_OP_LOGIN;
+	req_pdu->bhs.immediate = 1;
+	req_pdu->bhs.reserved = 0;
+	req_pdu->bhs_valid_bytes = ISCSI_BHS_LEN;
+	req_pdu->bhs.total_ahs_len = 0;
+
+	/* An initiator that chooses to operate without iSCSI security and with
+	 * all the operational parameters taking the default values issues the
+	 * Login with the T bit set to 1, the CSG set to
+	 * LoginOperationalNegotiation, and the NSG set to FullFeaturePhase.
+	 *
+	 * Byte /	   0	   |	   1	   |	   2	   |	   3	   |
+	 *	   |0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|
+	 *	   +---------------+---------------+---------------+---------------+
+	 *	  0|.|1| 0x03	   |T|C|.|.|CSG|NSG| Version-max   | Version-min   |
+	 */
+	req_pdu->bhs.flags = ISCSI_LOGIN_TRANSIT | (ISCSI_OPERATIONAL_NEGOTIATION_PHASE << 2) |
+			     ISCSI_FULL_FEATURE_PHASE;
+
+	req_pdu->data_segment_len = iscsi_append_text(conn, "InitiatorName", g_init_name,
+				    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
+	req_pdu->data_segment_len = iscsi_append_text(conn, "HeaderDigest", "None",
+				    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
+	req_pdu->data_segment_len = iscsi_append_text(conn, "DataDigest", "None",
+				    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
+	req_pdu->data_segment_len = iscsi_append_text(conn, "DefaultTime2Wait", "2",
+				    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
+	req_pdu->data_segment_len = iscsi_append_text(conn, "DefaultTime2Retain", "0",
+				    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
+	req_pdu->data_segment_len = iscsi_append_text(conn, "IFMarker", "No",
+				    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
+	req_pdu->data_segment_len = iscsi_append_text(conn, "OFMarker", "No",
+				    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
+	req_pdu->data_segment_len = iscsi_append_text(conn, "ErrorRecoveryLevel", "0",
+				    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
+
+	if (session_type == SESSION_TYPE_DISCOVERY) {
+		/* Discovery PDU */
+		conn->sess->session_type = SESSION_TYPE_DISCOVERY;
+		req_pdu->data_segment_len = iscsi_append_text(conn, "SessionType", "Discovery",
+					    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
+		req_pdu->data_segment_len = iscsi_append_text(conn, "MaxRecvDataSegmentLength", "32768",
+					    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
+	} else {
+		/* Login PDU */
+		conn->sess->session_type = SESSION_TYPE_NORMAL;
+		req_pdu->data_segment_len = iscsi_append_text(conn, "SessionType", "Normal",
+					    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
+		req_pdu->data_segment_len = iscsi_append_text(conn, "TargetName", g_tgt_name,
+					    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
+		req_pdu->data_segment_len = iscsi_append_text(conn, "InitialR2T", "No",
+					    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
+		req_pdu->data_segment_len = iscsi_append_text(conn, "ImmediateData", "Yes",
+					    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
+		req_pdu->data_segment_len = iscsi_append_text(conn, "MaxBurstLength", "16776192",
+					    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
+		req_pdu->data_segment_len = iscsi_append_text(conn, "FirstBurstLength", "262144",
+					    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
+		req_pdu->data_segment_len = iscsi_append_text(conn, "MaxOutstandingR2T", "1",
+					    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
+		req_pdu->data_segment_len = iscsi_append_text(conn, "MaxConnections", "1",
+					    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
+		req_pdu->data_segment_len = iscsi_append_text(conn, "DataPDUInOrder", "Yes",
+					    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
+		req_pdu->data_segment_len = iscsi_append_text(conn, "DataSequenceInOrder", "Yes",
+					    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
+		req_pdu->data_segment_len = iscsi_append_text(conn, "MaxRecvDataSegmentLength", "262144",
+					    req_pdu->data, req_pdu->data_buf_len, req_pdu->data_segment_len);
+	}
+
+	DSET24(req_pdu->bhs.data_segment_len, req_pdu->data_segment_len);
+	iscsi_conn_write_pdu(conn, req_pdu, iscsi_conn_pdu_generic_complete, NULL);
+}
+
+static void
+fuzz_iscsi_send_logout_request(struct fuzz_iscsi_dev_ctx *dev_ctx)
+{
+	struct fuzz_iscsi_io_ctx *io_ctx = NULL;
+	struct spdk_iscsi_pdu *req_pdu;
+	struct iscsi_bhs_logout_req *logout_req;
+	struct spdk_iscsi_conn *conn = dev_ctx->conn;
+
+	conn->is_logged_out = true;
+
+	req_pdu = iscsi_get_pdu(conn);
+	req_pdu->writev_offset = 0;
+	req_pdu->hdigest_valid_bytes = 0;
+	req_pdu->ahs_valid_bytes = 0;
+	req_pdu->data_buf_len = 0;
+
+	logout_req = (struct iscsi_bhs_logout_req *)&req_pdu->bhs;
+	io_ctx = &dev_ctx->io_ctx;
+	io_ctx->req.logout_req = logout_req;
+
+	req_pdu->bhs.opcode = ISCSI_OP_LOGOUT;
+	req_pdu->bhs.immediate = 1;
+	req_pdu->bhs.reserved = 0;
+	req_pdu->bhs_valid_bytes = ISCSI_BHS_LEN;
+	req_pdu->bhs.total_ahs_len = 0;
+	req_pdu->bhs.flags = 0;
+
+	DSET24(req_pdu->bhs.data_segment_len, 0);
+	iscsi_conn_write_pdu(conn, req_pdu, iscsi_conn_pdu_generic_complete, conn);
+}
+
+static void
+iscsi_fuzz_conn_reset(struct spdk_iscsi_conn *conn, struct spdk_iscsi_sess *sess)
+{
+	conn->sess = sess;
+	conn->data_in_cnt = 0;
+	conn->params = NULL;
+	conn->header_digest = true;
+	conn->data_digest = false;
+	conn->header_digest = 0;
+	conn->MaxRecvDataSegmentLength = 8192;
+	conn->full_feature = 0;
+	conn->pdu_recv_state = ISCSI_PDU_RECV_STATE_AWAIT_PDU_READY;
+	conn->pdu_in_progress = NULL;
+	conn->is_logged_out = 0;
+}
+
+static void
+iscsi_fuzz_sock_connect(struct spdk_iscsi_conn *conn)
+{
+	const char *host = g_tgt_ip;
+	const char *port = g_tgt_port;
+	char saddr[INET6_ADDRSTRLEN], caddr[INET6_ADDRSTRLEN];
+	uint16_t cport, sport;
+	int rc = 0;
+
+	conn->sock = spdk_sock_connect(host, spdk_strtol(port, 10), NULL);
+	if (conn->sock == NULL) {
+		fprintf(stderr, "connect error(%d): %s\n", errno, spdk_strerror(errno));
+		spdk_sock_close(&conn->sock);
+		return;
+	}
+	fprintf(stderr, "\nConnecting to the server on %s:%s\n", host, port);
+
+	rc = spdk_sock_getaddr(conn->sock, saddr, sizeof(saddr), &sport, caddr, sizeof(caddr), &cport);
+	if (rc < 0) {
+		fprintf(stderr, "Cannot get connection addresses\n");
+		spdk_sock_close(&conn->sock);
+		return;
+	}
+
+	fprintf(stderr, "Connection accepted from (%s, %hu) to (%s, %hu)\n", caddr, cport, saddr, sport);
+
+}
+
+static void
+check_successful_op(struct fuzz_iscsi_dev_ctx *dev_ctx, struct fuzz_iscsi_io_ctx *io_ctx)
+{
+	if (g_is_valid_opcode) {
+		fprintf(stderr, "Sent a valid opcode PDU.\n");
+		dev_ctx->num_valid_pdus++;
+	} else {
+		fprintf(stderr, "Sent an invalid opcode PDU.\n");
+	}
+}
+
+/* submit requests begin */
+static void
+dev_submit_requests(struct fuzz_iscsi_dev_ctx *dev_ctx)
+{
+	struct fuzz_iscsi_io_ctx *io_ctx = NULL;
+	uint8_t opcode;
+	struct spdk_iscsi_pdu *req_pdu;
+	struct iscsi_bhs *bhs;
+	struct iscsi_bhs_nop_out *nop_out_req;
+	struct iscsi_bhs_scsi_req *scsi_req;
+	struct iscsi_bhs_task_req *task_req;
+	struct iscsi_bhs_text_req *text_req;
+	struct iscsi_bhs_data_out *data_out_req;
+	struct iscsi_bhs_snack_req *snack_req;
+	unsigned int rand_seed;
+	bool is_p99;
+
+	g_is_valid_opcode = true;
+
+	/* Random PDU */
+	opcode = rand() % 0x3f;
+	fprintf(stderr,	"Random request bhs.opcode of Initiator is 0x%x.\n", opcode);
+
+	if ((opcode == ISCSI_OP_LOGIN) || (opcode == ISCSI_OP_LOGOUT)) {
+		/* only need send next */
+		fprintf(stderr, "LOGIN and LOGOUT opcodes are ignored here.\n");
+		return;
+	}
+
+	req_pdu = iscsi_get_pdu(dev_ctx->conn);
+	req_pdu->writev_offset = 0;
+	req_pdu->hdigest_valid_bytes = 0;
+	req_pdu->ahs_valid_bytes = 0;
+	req_pdu->data_buf_len = 0;
+
+	dev_ctx->conn->sess->session_type = SESSION_TYPE_NORMAL;
+
+	io_ctx = &dev_ctx->io_ctx;
+
+	switch (opcode) {
+	case ISCSI_OP_NOPOUT:
+		nop_out_req = (struct iscsi_bhs_nop_out *)&req_pdu->bhs;
+		io_ctx->req.nop_out_req = nop_out_req;
+		break;
+	case ISCSI_OP_SCSI:
+		scsi_req = (struct iscsi_bhs_scsi_req *)&req_pdu->bhs;
+		io_ctx->req.scsi_req = scsi_req;
+		break;
+	case ISCSI_OP_TASK:
+		task_req = (struct iscsi_bhs_task_req *)&req_pdu->bhs;
+		io_ctx->req.task_req = task_req;
+		break;
+	case ISCSI_OP_TEXT:
+		text_req = (struct iscsi_bhs_text_req *)&req_pdu->bhs;
+		io_ctx->req.text_req = text_req;
+		break;
+	case ISCSI_OP_SCSI_DATAOUT:
+		data_out_req = (struct iscsi_bhs_data_out *)&req_pdu->bhs;
+		io_ctx->req.data_out_req = data_out_req;
+		break;
+	case ISCSI_OP_SNACK:
+		snack_req = (struct iscsi_bhs_snack_req *)&req_pdu->bhs;
+		io_ctx->req.snack_req = snack_req;
+		break;
+	default:
+		bhs = (struct iscsi_bhs *)&req_pdu->bhs;
+		io_ctx->req.bhs = bhs;
+		g_is_valid_opcode = false;
+		break;
+	}
+
+	prep_iscsi_pdu_bhs_opcode_cmd(dev_ctx, io_ctx);
+	io_ctx->req.bhs->opcode = opcode;
+	req_pdu->bhs.opcode = opcode;
+	req_pdu->bhs.immediate = 1;
+	req_pdu->bhs.reserved = 0;
+	req_pdu->bhs_valid_bytes = ISCSI_BHS_LEN;
+	req_pdu->bhs.total_ahs_len = 0;
+	req_pdu->bhs.stat_sn = 0;
+	DSET24(req_pdu->bhs.data_segment_len, 0);
+
+	if (opcode <= ISCSI_OP_TEXT) {
+		rand_seed = time(NULL);
+		is_p99 = rand_r(&rand_seed) % 100 == 0 ? true : false;
+		if (!is_p99) { /* Remaining 1% */
+			switch (opcode) {
+			case ISCSI_OP_NOPOUT:
+				if (req_pdu->bhs.immediate) {
+					io_ctx->req.nop_out_req->cmd_sn = dev_ctx->current_cmd_sn;
+				} else {
+					io_ctx->req.nop_out_req->cmd_sn = dev_ctx->current_cmd_sn++;
+				}
+				break;
+			case ISCSI_OP_SCSI:
+				if (req_pdu->bhs.immediate) {
+					io_ctx->req.scsi_req->cmd_sn = dev_ctx->current_cmd_sn;
+				} else {
+					io_ctx->req.scsi_req->cmd_sn = dev_ctx->current_cmd_sn++;
+				}
+				break;
+			case ISCSI_OP_TASK:
+				if (req_pdu->bhs.immediate) {
+					io_ctx->req.task_req->cmd_sn = dev_ctx->current_cmd_sn;
+				} else {
+					io_ctx->req.task_req->cmd_sn = dev_ctx->current_cmd_sn++;
+				}
+				break;
+			case ISCSI_OP_TEXT:
+				if (req_pdu->bhs.immediate) {
+					io_ctx->req.text_req->cmd_sn = dev_ctx->current_cmd_sn;
+				} else {
+					io_ctx->req.text_req->cmd_sn = dev_ctx->current_cmd_sn++;
+				}
+				break;
+			default:
+				break;
+			}
+		}
+	}
+
+	if (opcode == ISCSI_OP_SCSI) {
+		/* avoid ((R_bit != 0) && (W_bit != 0)) is true */
+		io_ctx->req.scsi_req->read_bit = 0;
+		io_ctx->req.scsi_req->write_bit = 0;
+	}
+
+	if (opcode == ISCSI_OP_TEXT) {
+		/* avoid: (F_bit && C_bit) is true */
+		io_ctx->req.text_req->flags = 0;
+		/* avoid: correct itt is not equal to the current itt */
+		io_ctx->req.text_req->itt = 0;
+	}
+
+	fprintf(stderr, "Dumping this request bhs contents now.\n");
+	print_req_obj(dev_ctx, io_ctx);
+
+	check_successful_op(dev_ctx, io_ctx);
+	dev_ctx->num_sent_pdus++;
+
+	iscsi_conn_write_pdu(dev_ctx->conn, req_pdu,
+			     iscsi_conn_pdu_generic_complete, NULL);
+}
+/* submit requests end */
+
+static int
+poll_dev(void *ctx)
+{
+	struct fuzz_iscsi_dev_ctx *dev_ctx = ctx;
+	struct spdk_iscsi_conn *conn = dev_ctx->conn;
+	uint64_t current_ticks;
+	struct spdk_iscsi_pdu *pdu, *tmp;
+
+	current_ticks = spdk_get_ticks();
+	if (current_ticks > g_runtime_ticks) {
+		g_run = false;
+	}
+
+	if (!g_run) {
+		/* Logout PDU */
+		fuzz_iscsi_send_logout_request(dev_ctx);
+		fuzz_iscsi_handle_incoming_pdus(conn);
+
+		TAILQ_FOREACH_SAFE(pdu, &g_get_pdu_list, tailq, tmp) {
+			TAILQ_REMOVE(&g_get_pdu_list, pdu, tailq);
+			iscsi_put_pdu(pdu);
+		}
+
+		spdk_sock_close(&conn->sock);
+
+		TAILQ_FOREACH_SAFE(pdu, &conn->write_pdu_list, tailq, tmp) {
+			TAILQ_REMOVE(&conn->write_pdu_list, pdu, tailq);
+			iscsi_put_pdu(pdu);
+		}
+
+		free(conn);
+
+		spdk_poller_unregister(&dev_ctx->poller);
+		__sync_sub_and_fetch(&g_num_active_threads, 1);
+
+		return -1;
+	}
+
+	if (conn->is_logged_out) {
+		spdk_sock_close(&conn->sock);
+		iscsi_fuzz_conn_reset(conn, &dev_ctx->sess);
+		iscsi_fuzz_sock_connect(conn);
+		usleep(1000);
+
+		/* Login PDU */
+		fuzz_iscsi_send_login_request(dev_ctx, SESSION_TYPE_NORMAL);
+	} else if (conn->full_feature == 1) {
+		dev_submit_requests(dev_ctx);
+	}
+
+	spdk_sock_flush(conn->sock);
+
+	fuzz_iscsi_handle_incoming_pdus(conn);
+
+	return 0;
+}
+
+static void
+start_io(void *ctx)
+{
+	struct fuzz_iscsi_dev_ctx *dev_ctx = ctx;
+
+	dev_ctx->sess.ExpCmdSN = 0;
+	dev_ctx->sess.MaxCmdSN = 64;
+	dev_ctx->sess.MaxBurstLength = SPDK_ISCSI_MAX_RECV_DATA_SEGMENT_LENGTH;
+	dev_ctx->sess.MaxOutstandingR2T = 1;
+	dev_ctx->sess.tag = 1;
+	dev_ctx->sess.tsih = 256;
+
+	dev_ctx->conn = calloc(1, sizeof(*dev_ctx->conn));
+	assert(dev_ctx->conn != NULL);
+	TAILQ_INIT(&dev_ctx->conn->write_pdu_list);
+
+	iscsi_fuzz_conn_reset(dev_ctx->conn, &dev_ctx->sess);
+	iscsi_fuzz_sock_connect(dev_ctx->conn);
+	usleep(1000);
+
+	/* Login PDU */
+	fuzz_iscsi_send_login_request(dev_ctx, SESSION_TYPE_NORMAL);
+
+	if (g_random_seed) {
+		dev_ctx->random_seed = g_random_seed;
+	} else {
+		dev_ctx->random_seed = spdk_get_ticks();
+	}
+
+	dev_ctx->poller = SPDK_POLLER_REGISTER(poll_dev, dev_ctx, 0);
+	if (dev_ctx->poller == NULL) {
+		return;
+	}
+}
+
+static int
+check_app_completion(void *ctx)
+{
+	if (g_num_active_threads == 0) {
+		spdk_poller_unregister(&g_app_completion_poller);
+		printf("Fuzzing completed. Shutting down the fuzz application.\n\n");
+		cleanup();
+		spdk_app_stop(0);
+	}
+	return 0;
+}
+
+static void
+begin_iscsi_fuzz(void *ctx)
+{
+	struct fuzz_iscsi_dev_ctx *dev_ctx;
+	int rc;
+
+	g_runtime_ticks = spdk_get_ticks() + g_runtime * spdk_get_ticks_hz();
+
+	g_valid_buffer = spdk_malloc(0x1000, 0x200, NULL, SPDK_ENV_LCORE_ID_ANY, SPDK_MALLOC_SHARE);
+	if (g_valid_buffer == NULL) {
+		fprintf(stderr, "Failed to allocate a valid buffer for random PDUs\n");
+		goto out;
+	}
+
+	rc = fuzz_iscsi_dev_init();
+	if (rc) {
+		fprintf(stderr, "fuzz_iscsi_dev_init() failed.\n");
+		goto out;
+	}
+
+	TAILQ_FOREACH(dev_ctx, &g_dev_list, link) {
+		assert(dev_ctx->thread != NULL);
+		spdk_thread_send_msg(dev_ctx->thread, start_io, dev_ctx);
+		__sync_add_and_fetch(&g_num_active_threads, 1);
+	}
+
+	g_app_completion_poller = SPDK_POLLER_REGISTER(check_app_completion, NULL, 1000000);
+	if (g_app_completion_poller == NULL) {
+		fprintf(stderr, "Failed to register a poller for test completion checking.\n");
+		goto out;
+	}
+
+	return;
+out:
+	cleanup();
+	spdk_app_stop(0);
+}
+
+static void
+iscsi_fuzz_usage(void)
+{
+	fprintf(stderr, " -T <path>                 iSCSI Target IP address.\n");
+	fprintf(stderr, " -S <integer>              Seed value for test.\n");
+	fprintf(stderr,
+		" -t <integer>              Time in seconds to run the fuzz test. Only valid if -j is not specified.\n");
+}
+
+static int
+iscsi_fuzz_parse(int ch, char *arg)
+{
+	int64_t error_test;
+
+	switch (ch) {
+	case 'T':
+		g_tgt_ip = optarg;
+		break;
+	case 'S':
+		error_test = spdk_strtol(arg, 10);
+		if (error_test < 0) {
+			fprintf(stderr, "Invalid value supplied for the random seed.\n");
+			return -1;
+		} else {
+			g_random_seed = error_test;
+		}
+		break;
+	case 't':
+		g_runtime = spdk_strtol(optarg, 10);
+		if (g_runtime <= 0 || g_runtime > MAX_RUNTIME_S) {
+			fprintf(stderr, "You must supply a positive runtime value less than %d.\n", MAX_RUNTIME_S);
+			return -1;
+		}
+		break;
+	case '?':
+	default:
+		iscsi_fuzz_usage();
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+int
+main(int argc, char **argv)
+{
+	struct spdk_app_opts opts = {};
+	int rc;
+
+	g_runtime = DEFAULT_RUNTIME;
+	srand((unsigned)time(0));
+
+	TAILQ_INIT(&g_get_pdu_list);
+
+	spdk_app_opts_init(&opts);
+	opts.name = "iscsi_fuzz";
+
+	if ((rc = spdk_app_parse_args(argc, argv, &opts, "T:S:t:", NULL, iscsi_fuzz_parse,
+				      iscsi_fuzz_usage) != SPDK_APP_PARSE_ARGS_SUCCESS)) {
+		return rc;
+	}
+
+	rc = spdk_app_start(&opts, begin_iscsi_fuzz, NULL);
+
+	return rc;
+}
diff --git a/src/spdk/test/app/fuzz/nvme_fuzz/.gitignore b/src/spdk/test/app/fuzz/nvme_fuzz/.gitignore
new file mode 100644
index 000000000..801146458
--- /dev/null
+++ b/src/spdk/test/app/fuzz/nvme_fuzz/.gitignore
@@ -0,0 +1 @@
+nvme_fuzz
diff --git a/src/spdk/test/app/fuzz/nvme_fuzz/Makefile b/src/spdk/test/app/fuzz/nvme_fuzz/Makefile
new file mode 100644
index 000000000..b7ad5e172
--- /dev/null
+++ b/src/spdk/test/app/fuzz/nvme_fuzz/Makefile
@@ -0,0 +1,49 @@
+#
+#  Copyright (c) Intel Corporation.
+#  All rights reserved.
+#
+#  Redistribution and use in source and binary forms, with or without
+#  modification, are permitted provided that the following conditions
+#  are met:
+#
+#    * Redistributions of source code must retain the above copyright
+#      notice, this list of conditions and the following disclaimer.
+#    * Redistributions in binary form must reproduce the above copyright
+#      notice, this list of conditions and the following disclaimer in
+#      the documentation and/or other materials provided with the
+#      distribution.
+#    * Neither the name of Intel Corporation nor the names of its
+#      contributors may be used to endorse or promote products derived
+#      from this software without specific prior written permission.
+#
+#  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+#  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+#  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+#  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+#  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+#  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+#  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+#  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+#  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+#  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+#  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#
+
+SPDK_ROOT_DIR := $(abspath $(CURDIR)/../../../..)
+include $(SPDK_ROOT_DIR)/mk/spdk.common.mk
+include $(SPDK_ROOT_DIR)/mk/spdk.modules.mk
+
+APP = nvme_fuzz
+
+CFLAGS += -I$(SPDK_ROOT_DIR)/test/app/fuzz/common
+
+C_SRCS := nvme_fuzz.c
+
+SPDK_LIB_LIST += $(SOCK_MODULES_LIST)
+SPDK_LIB_LIST += conf event json jsonrpc log nvme rpc sock thread trace util
+
+ifeq ($(CONFIG_RDMA),y)
+SPDK_LIB_LIST += rdma
+endif
+
+include $(SPDK_ROOT_DIR)/mk/spdk.app.mk
diff --git a/src/spdk/test/app/fuzz/nvme_fuzz/README.md b/src/spdk/test/app/fuzz/nvme_fuzz/README.md
new file mode 100644
index 000000000..2f188b5b8
--- /dev/null
+++ b/src/spdk/test/app/fuzz/nvme_fuzz/README.md
@@ -0,0 +1,52 @@
+# Overview
+
+This application is intended to fuzz test the NVMe-oF target or a physical NVMe drive by
+submitting randomized NVMe commands through the SPDK NVMe initiator. Both local and remote
+drives are configured through a .ini style config file (See the -C option on the application).
+Multiple controllers and namespaces can be exposed to the fuzzer at a time. In order to
+handle multiple namespaces, the fuzzer will round robin assign a thread to each namespace and
+submit commands to that thread at a set queue depth. (currently 128 for I/O, 16 for Admin). The
+application will terminate under three conditions:
+
+1. The user specified run time expires (see the -t flag).
+2. One of the target controllers stops completing I/O operations back to the fuzzer i.e. controller timeout.
+3. The user specified a json file containing operations to run and the fuzzer has received valid completions for all of them.
+
+# Output
+
+By default, the fuzzer will print commands that:
+
+1. Complete successfully back from the target, or
+2. Are outstanding at the time of a controller timeout.
+
+Commands are dumped as named objects in json format which can then be supplied back to the
+script for targeted debugging on a subsequent run. See `Debugging` below.
+By default no output is generated when a specific command is returned with a failed status.
+This can be overridden with the -V flag. if -V is specified, each command will be dumped as
+it is completed in the JSON format specified above.
+At the end of each test run, a summary is printed for each namespace in the following format:
+
+~~~
+NS: 0x200079262300 admin qp, Total commands completed: 462459, total successful commands: 1960, random_seed: 4276918833
+~~~
+
+# Debugging
+
+If a controller hangs when processing I/O generated by the fuzzer, the fuzzer will stop
+submitting I/O and dump out all outstanding I/O on the qpair that timed out. The I/O are
+dumped as valid json. You can combine the dumped commands from the fuzzer into a json
+array in a file and then pass them to the fuzzer using the -j option. Please see the
+example.json file in this directory for an example of a properly formed array of command
+structures.
+
+Please note that you can also craft your own custom command values by using the output
+from the fuzzer as a template.
+
+# JSON Format
+
+Most of the variables in the spdk_nvme_cmd structure are represented as numbers in JSON.
+The only exception to this rule is the dptr union. This is a 16 byte union structure that
+is represented as a base64 string. If writing custom commands for input, please note this
+distinction or the application will be unable to load your custom input.
+
+Happy Fuzzing!
diff --git a/src/spdk/test/app/fuzz/nvme_fuzz/example.json b/src/spdk/test/app/fuzz/nvme_fuzz/example.json
new file mode 100644
index 000000000..95540746e
--- /dev/null
+++ b/src/spdk/test/app/fuzz/nvme_fuzz/example.json
@@ -0,0 +1,290 @@
+{
+"struct spdk_nvme_cmd": {
+  "opc": 7,
+  "fuse": 1,
+  "rsvd1": 13,
+  "psdt": 1,
+  "cid": 56732,
+  "nsid": 1,
+  "rsvd2": 1516848792,
+  "rsvd3": 1233945838,
+  "mptr": 3452736735,
+  "dptr": "FHENPcH+xM0tioD+0SrNrQ==",
+  "cdw10": 3190735246,
+  "cdw11": 2629178873,
+  "cdw12": 138580308,
+  "cdw13": 1603605200,
+  "cdw14": 3031880384,
+  "cdw15": 644909208
+  },
+  "struct spdk_nvme_cmd": {
+  "opc": 24,
+  "fuse": 1,
+  "rsvd1": 13,
+  "psdt": 1,
+  "cid": 56732,
+  "nsid": 1,
+  "rsvd2": 1516848792,
+  "rsvd3": 1233945838,
+  "mptr": 3452736735,
+  "dptr": "FHENPcH+xM0tioD+0SrNrQ==",
+  "cdw10": 3190735246,
+  "cdw11": 2629178873,
+  "cdw12": 138580308,
+  "cdw13": 1603605200,
+  "cdw14": 3031880384,
+  "cdw15": 644909208
+  },
+  "struct spdk_nvme_cmd": {
+  "opc": 43,
+  "fuse": 1,
+  "rsvd1": 13,
+  "psdt": 1,
+  "cid": 56732,
+  "nsid": 1,
+  "rsvd2": 1516848792,
+  "rsvd3": 1233945838,
+  "mptr": 3452736735,
+  "dptr": "FHENPcH+xM0tioD+0SrNrQ==",
+  "cdw10": 3190735246,
+  "cdw11": 2629178873,
+  "cdw12": 138580308,
+  "cdw13": 1603605200,
+  "cdw14": 3031880384,
+  "cdw15": 644909208
+  },
+  "struct spdk_nvme_cmd": {
+  "opc": 12,
+  "fuse": 1,
+  "rsvd1": 13,
+  "psdt": 1,
+  "cid": 56732,
+  "nsid": 1,
+  "rsvd2": 1516848792,
+  "rsvd3": 1233945838,
+  "mptr": 3452736735,
+  "dptr": "FHENPcH+xM0tioD+0SrNrQ==",
+  "cdw10": 3190735246,
+  "cdw11": 2629178873,
+  "cdw12": 138580308,
+  "cdw13": 1603605200,
+  "cdw14": 3031880384,
+  "cdw15": 644909208
+  },
+  "struct spdk_nvme_cmd": {
+    "opc": 7,
+    "fuse": 1,
+    "rsvd1": 13,
+    "psdt": 1,
+    "cid": 56732,
+    "nsid": 1,
+    "rsvd2": 1516848792,
+    "rsvd3": 1233945838,
+    "mptr": 3452736735,
+    "dptr": "FHENPcH+xM0tioD+0SrNrQ==",
+    "cdw10": 3190735246,
+    "cdw11": 2629178873,
+    "cdw12": 138580308,
+    "cdw13": 1603605200,
+    "cdw14": 3031880384,
+    "cdw15": 644909208
+    },
+    "struct spdk_nvme_cmd": {
+    "opc": 24,
+    "fuse": 1,
+    "rsvd1": 13,
+    "psdt": 1,
+    "cid": 56732,
+    "nsid": 1,
+    "rsvd2": 1516848792,
+    "rsvd3": 1233945838,
+    "mptr": 3452736735,
+    "dptr": "FHENPcH+xM0tioD+0SrNrQ==",
+    "cdw10": 3190735246,
+    "cdw11": 2629178873,
+    "cdw12": 138580308,
+    "cdw13": 1603605200,
+    "cdw14": 3031880384,
+    "cdw15": 644909208
+    },
+    "struct spdk_nvme_cmd": {
+    "opc": 43,
+    "fuse": 1,
+    "rsvd1": 13,
+    "psdt": 1,
+    "cid": 56732,
+    "nsid": 1,
+    "rsvd2": 1516848792,
+    "rsvd3": 1233945838,
+    "mptr": 3452736735,
+    "dptr": "FHENPcH+xM0tioD+0SrNrQ==",
+    "cdw10": 3190735246,
+    "cdw11": 2629178873,
+    "cdw12": 138580308,
+    "cdw13": 1603605200,
+    "cdw14": 3031880384,
+    "cdw15": 644909208
+    },
+    "struct spdk_nvme_cmd": {
+    "opc": 12,
+    "fuse": 1,
+    "rsvd1": 13,
+    "psdt": 1,
+    "cid": 56732,
+    "nsid": 1,
+    "rsvd2": 1516848792,
+    "rsvd3": 1233945838,
+    "mptr": 3452736735,
+    "dptr": "FHENPcH+xM0tioD+0SrNrQ==",
+    "cdw10": 3190735246,
+    "cdw11": 2629178873,
+    "cdw12": 138580308,
+    "cdw13": 1603605200,
+    "cdw14": 3031880384,
+    "cdw15": 644909208
+    },
+    "struct spdk_nvme_cmd": {
+      "opc": 7,
+      "fuse": 1,
+      "rsvd1": 13,
+      "psdt": 1,
+      "cid": 56732,
+      "nsid": 1,
+      "rsvd2": 1516848792,
+      "rsvd3": 1233945838,
+      "mptr": 3452736735,
+      "dptr": "FHENPcH+xM0tioD+0SrNrQ==",
+      "cdw10": 3190735246,
+      "cdw11": 2629178873,
+      "cdw12": 138580308,
+      "cdw13": 1603605200,
+      "cdw14": 3031880384,
+      "cdw15": 644909208
+      },
+      "struct spdk_nvme_cmd": {
+      "opc": 24,
+      "fuse": 1,
+      "rsvd1": 13,
+      "psdt": 1,
+      "cid": 56732,
+      "nsid": 1,
+      "rsvd2": 1516848792,
+      "rsvd3": 1233945838,
+      "mptr": 3452736735,
+      "dptr": "FHENPcH+xM0tioD+0SrNrQ==",
+      "cdw10": 3190735246,
+      "cdw11": 2629178873,
+      "cdw12": 138580308,
+      "cdw13": 1603605200,
+      "cdw14": 3031880384,
+      "cdw15": 644909208
+      },
+      "struct spdk_nvme_cmd": {
+      "opc": 43,
+      "fuse": 1,
+      "rsvd1": 13,
+      "psdt": 1,
+      "cid": 56732,
+      "nsid": 1,
+      "rsvd2": 1516848792,
+      "rsvd3": 1233945838,
+      "mptr": 3452736735,
+      "dptr": "FHENPcH+xM0tioD+0SrNrQ==",
+      "cdw10": 3190735246,
+      "cdw11": 2629178873,
+      "cdw12": 138580308,
+      "cdw13": 1603605200,
+      "cdw14": 3031880384,
+      "cdw15": 644909208
+      },
+      "struct spdk_nvme_cmd": {
+      "opc": 12,
+      "fuse": 1,
+      "rsvd1": 13,
+      "psdt": 1,
+      "cid": 56732,
+      "nsid": 1,
+      "rsvd2": 1516848792,
+      "rsvd3": 1233945838,
+      "mptr": 3452736735,
+      "dptr": "FHENPcH+xM0tioD+0SrNrQ==",
+      "cdw10": 3190735246,
+      "cdw11": 2629178873,
+      "cdw12": 138580308,
+      "cdw13": 1603605200,
+      "cdw14": 3031880384,
+      "cdw15": 644909208
+      },
+      "struct spdk_nvme_cmd": {
+        "opc": 7,
+        "fuse": 1,
+        "rsvd1": 13,
+        "psdt": 1,
+        "cid": 56732,
+        "nsid": 1,
+        "rsvd2": 1516848792,
+        "rsvd3": 1233945838,
+        "mptr": 3452736735,
+        "dptr": "FHENPcH+xM0tioD+0SrNrQ==",
+        "cdw10": 3190735246,
+        "cdw11": 2629178873,
+        "cdw12": 138580308,
+        "cdw13": 1603605200,
+        "cdw14": 3031880384,
+        "cdw15": 644909208
+        },
+        "struct spdk_nvme_cmd": {
+        "opc": 24,
+        "fuse": 1,
+        "rsvd1": 13,
+        "psdt": 1,
+        "cid": 56732,
+        "nsid": 1,
+        "rsvd2": 1516848792,
+        "rsvd3": 1233945838,
+        "mptr": 3452736735,
+        "dptr": "FHENPcH+xM0tioD+0SrNrQ==",
+        "cdw10": 3190735246,
+        "cdw11": 2629178873,
+        "cdw12": 138580308,
+        "cdw13": 1603605200,
+        "cdw14": 3031880384,
+        "cdw15": 644909208
+        },
+        "struct spdk_nvme_cmd": {
+        "opc": 43,
+        "fuse": 1,
+        "rsvd1": 13,
+        "psdt": 1,
+        "cid": 56732,
+        "nsid": 1,
+        "rsvd2": 1516848792,
+        "rsvd3": 1233945838,
+        "mptr": 3452736735,
+        "dptr": "FHENPcH+xM0tioD+0SrNrQ==",
+        "cdw10": 3190735246,
+        "cdw11": 2629178873,
+        "cdw12": 138580308,
+        "cdw13": 1603605200,
+        "cdw14": 3031880384,
+        "cdw15": 644909208
+        },
+        "struct spdk_nvme_cmd": {
+        "opc": 12,
+        "fuse": 1,
+        "rsvd1": 13,
+        "psdt": 1,
+        "cid": 56732,
+        "nsid": 1,
+        "rsvd2": 1516848792,
+        "rsvd3": 1233945838,
+        "mptr": 3452736735,
+        "dptr": "FHENPcH+xM0tioD+0SrNrQ==",
+        "cdw10": 3190735246,
+        "cdw11": 2629178873,
+        "cdw12": 138580308,
+        "cdw13": 1603605200,
+        "cdw14": 3031880384,
+        "cdw15": 644909208
+        }
+}
diff --git a/src/spdk/test/app/fuzz/nvme_fuzz/nvme_fuzz.c b/src/spdk/test/app/fuzz/nvme_fuzz/nvme_fuzz.c
new file mode 100644
index 000000000..127bc1bff
--- /dev/null
+++ b/src/spdk/test/app/fuzz/nvme_fuzz/nvme_fuzz.c
@@ -0,0 +1,931 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright (c) Intel Corporation. All rights reserved.
+ *   Copyright (c) 2019 Mellanox Technologies LTD. All rights reserved.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following conditions
+ *   are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in
+ *       the documentation and/or other materials provided with the
+ *       distribution.
+ *     * Neither the name of Intel Corporation nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "spdk/stdinc.h"
+#include "spdk/conf.h"
+#include "spdk/env.h"
+#include "spdk/event.h"
+#include "spdk/util.h"
+#include "spdk/string.h"
+#include "spdk/nvme_spec.h"
+#include "spdk/nvme.h"
+#include "spdk/likely.h"
+#include "spdk/json.h"
+#include "fuzz_common.h"
+
+#define UNIQUE_OPCODES 256
+
+const char g_nvme_cmd_json_name[] = "struct spdk_nvme_cmd";
+char *g_conf_file;
+char *g_json_file = NULL;
+uint64_t g_runtime_ticks;
+unsigned int g_seed_value = 0;
+int g_runtime;
+
+int g_num_active_threads = 0;
+uint32_t g_admin_depth = 16;
+uint32_t g_io_depth = 128;
+
+bool g_valid_ns_only = false;
+bool g_verbose_mode = false;
+bool g_run_admin_commands = false;
+bool g_run;
+
+struct spdk_poller *g_app_completion_poller;
+bool g_successful_io_opcodes[UNIQUE_OPCODES] = {0};
+bool g_successful_admin_opcodes[UNIQUE_OPCODES] = {0};
+
+struct spdk_nvme_cmd *g_cmd_array;
+size_t g_cmd_array_size;
+
+/* I need context objects here because I need to keep track of all I/O that are in flight. */
+struct nvme_fuzz_request {
+	struct spdk_nvme_cmd		cmd;
+	struct nvme_fuzz_qp		*qp;
+	TAILQ_ENTRY(nvme_fuzz_request)	link;
+};
+
+struct nvme_fuzz_trid {
+	struct spdk_nvme_transport_id	trid;
+	TAILQ_ENTRY(nvme_fuzz_trid)	tailq;
+};
+
+struct nvme_fuzz_ctrlr {
+	struct spdk_nvme_ctrlr		*ctrlr;
+	TAILQ_ENTRY(nvme_fuzz_ctrlr)	tailq;
+};
+
+struct nvme_fuzz_qp {
+	struct spdk_nvme_qpair		*qpair;
+	/* array of context objects equal in length to the queue depth */
+	struct nvme_fuzz_request	*req_ctx;
+	TAILQ_HEAD(, nvme_fuzz_request)	free_ctx_objs;
+	TAILQ_HEAD(, nvme_fuzz_request)	outstanding_ctx_objs;
+	unsigned int			random_seed;
+	uint64_t			completed_cmd_counter;
+	uint64_t			submitted_cmd_counter;
+	uint64_t			successful_completed_cmd_counter;
+	uint64_t			timeout_tsc;
+	uint32_t			num_cmds_outstanding;
+	bool				timed_out;
+	bool				is_admin;
+};
+
+struct nvme_fuzz_ns {
+	struct spdk_nvme_ns		*ns;
+	struct spdk_nvme_ctrlr		*ctrlr;
+	struct spdk_thread		*thread;
+	struct spdk_poller		*req_poller;
+	struct nvme_fuzz_qp		io_qp;
+	struct nvme_fuzz_qp		a_qp;
+	uint32_t			nsid;
+	TAILQ_ENTRY(nvme_fuzz_ns)	tailq;
+};
+
+static TAILQ_HEAD(, nvme_fuzz_ns) g_ns_list = TAILQ_HEAD_INITIALIZER(g_ns_list);
+static TAILQ_HEAD(, nvme_fuzz_ctrlr) g_ctrlr_list = TAILQ_HEAD_INITIALIZER(g_ctrlr_list);
+static TAILQ_HEAD(, nvme_fuzz_trid) g_trid_list = TAILQ_HEAD_INITIALIZER(g_trid_list);
+
+static bool
+parse_nvme_cmd_obj(void *item, struct spdk_json_val *value, size_t num_values)
+{
+	struct spdk_nvme_cmd *cmd = item;
+	struct spdk_json_val *next_val;
+	uint64_t tmp_val;
+	size_t i = 0;
+
+	while (i < num_values) {
+		if (value->type == SPDK_JSON_VAL_NAME) {
+			next_val = value + 1;
+			if (!strncmp(value->start, "opc", value->len)) {
+				if (next_val->type == SPDK_JSON_VAL_NUMBER) {
+					if (fuzz_parse_json_num(next_val, UNSIGNED_8BIT_MAX, &tmp_val)) {
+						goto invalid;
+					}
+					cmd->opc = tmp_val;
+				}
+			} else if (!strncmp(value->start, "fuse", value->len)) {
+				if (next_val->type == SPDK_JSON_VAL_NUMBER) {
+					if (fuzz_parse_json_num(next_val, UNSIGNED_2BIT_MAX, &tmp_val)) {
+						goto invalid;
+					}
+					cmd->fuse = tmp_val;
+				}
+			} else if (!strncmp(value->start, "rsvd1", value->len)) {
+				if (next_val->type == SPDK_JSON_VAL_NUMBER) {
+					if (fuzz_parse_json_num(next_val, UNSIGNED_4BIT_MAX, &tmp_val)) {
+						goto invalid;
+					}
+					cmd->rsvd1 = tmp_val;
+				}
+			} else if (!strncmp(value->start, "psdt", value->len)) {
+				if (next_val->type == SPDK_JSON_VAL_NUMBER) {
+					if (fuzz_parse_json_num(next_val, UNSIGNED_2BIT_MAX, &tmp_val)) {
+						goto invalid;
+					}
+					cmd->psdt = tmp_val;
+				}
+			} else if (!strncmp(value->start, "cid", value->len)) {
+				if (next_val->type == SPDK_JSON_VAL_NUMBER) {
+					if (fuzz_parse_json_num(next_val, UINT16_MAX, &tmp_val)) {
+						goto invalid;
+					}
+					cmd->cid = tmp_val;
+				}
+			} else if (!strncmp(value->start, "nsid", value->len)) {
+				if (next_val->type == SPDK_JSON_VAL_NUMBER) {
+					if (fuzz_parse_json_num(next_val, UINT32_MAX, &tmp_val)) {
+						goto invalid;
+					}
+					cmd->nsid = tmp_val;
+				}
+			} else if (!strncmp(value->start, "rsvd2", value->len)) {
+				if (next_val->type == SPDK_JSON_VAL_NUMBER) {
+					if (fuzz_parse_json_num(next_val, UINT32_MAX, &tmp_val)) {
+						goto invalid;
+					}
+					cmd->rsvd2 = tmp_val;
+				}
+			} else if (!strncmp(value->start, "rsvd3", value->len)) {
+				if (next_val->type == SPDK_JSON_VAL_NUMBER) {
+					if (fuzz_parse_json_num(next_val, UINT32_MAX, &tmp_val)) {
+						goto invalid;
+					}
+					cmd->rsvd3 = tmp_val;
+				}
+			} else if (!strncmp(value->start, "mptr", value->len)) {
+				if (next_val->type == SPDK_JSON_VAL_NUMBER) {
+					if (fuzz_parse_json_num(next_val, UINT64_MAX, &tmp_val)) {
+						goto invalid;
+					}
+					cmd->mptr = tmp_val;
+				}
+			} else if (!strncmp(value->start, "dptr", value->len)) {
+				if (next_val->type == SPDK_JSON_VAL_STRING) {
+					if (fuzz_get_base_64_buffer_value(&cmd->dptr, sizeof(cmd->dptr), (char *)next_val->start,
+									  next_val->len)) {
+						goto invalid;
+					}
+				}
+			} else if (!strncmp(value->start, "cdw10", value->len)) {
+				if (next_val->type == SPDK_JSON_VAL_NUMBER) {
+					if (fuzz_parse_json_num(next_val, UINT32_MAX, &tmp_val)) {
+						goto invalid;
+					}
+					cmd->cdw10 = tmp_val;
+				}
+			} else if (!strncmp(value->start, "cdw11", value->len)) {
+				if (next_val->type == SPDK_JSON_VAL_NUMBER) {
+					if (fuzz_parse_json_num(next_val, UINT32_MAX, &tmp_val)) {
+						goto invalid;
+					}
+					cmd->cdw11 = tmp_val;
+				}
+			} else if (!strncmp(value->start, "cdw12", value->len)) {
+				if (next_val->type == SPDK_JSON_VAL_NUMBER) {
+					if (fuzz_parse_json_num(next_val, UINT32_MAX, &tmp_val)) {
+						goto invalid;
+					}
+					cmd->cdw12 = tmp_val;
+				}
+			} else if (!strncmp(value->start, "cdw13", value->len)) {
+				if (next_val->type == SPDK_JSON_VAL_NUMBER) {
+					if (fuzz_parse_json_num(next_val, UINT32_MAX, &tmp_val)) {
+						goto invalid;
+					}
+					cmd->cdw13 = tmp_val;
+				}
+			} else if (!strncmp(value->start, "cdw14", value->len)) {
+				if (next_val->type == SPDK_JSON_VAL_NUMBER) {
+					if (fuzz_parse_json_num(next_val, UINT32_MAX, &tmp_val)) {
+						goto invalid;
+					}
+					cmd->cdw14 = tmp_val;
+				}
+			} else if (!strncmp(value->start, "cdw15", value->len)) {
+				if (next_val->type == SPDK_JSON_VAL_NUMBER) {
+					if (fuzz_parse_json_num(next_val, UINT32_MAX, &tmp_val)) {
+						goto invalid;
+					}
+					cmd->cdw15 = tmp_val;
+				}
+			}
+		}
+		i++;
+		value++;
+	}
+	return true;
+
+invalid:
+	fprintf(stderr, "Invalid value supplied for cmd->%.*s: %.*s\n", value->len, (char *)value->start,
+		next_val->len, (char *)next_val->start);
+	return false;
+}
+
+static void
+report_successful_opcodes(bool *array, int length)
+{
+	int i;
+
+	for (i = 0; i < length; i++) {
+		if (array[i] == true) {
+			printf("%d, ", i);
+		}
+	}
+	printf("\n");
+}
+
+static int
+print_nvme_cmd(void *cb_ctx, const void *data, size_t size)
+{
+	fprintf(stderr, "%s\n", (const char *)data);
+	return 0;
+}
+
+static void
+json_dump_nvme_cmd(struct spdk_nvme_cmd *cmd)
+{
+	struct spdk_json_write_ctx *w;
+	char *dptr_value;
+
+	dptr_value = fuzz_get_value_base_64_buffer(&cmd->dptr, sizeof(cmd->dptr));
+	if (dptr_value == NULL) {
+		fprintf(stderr, "Unable to allocate buffer context for printing command.\n");
+		return;
+	}
+
+	w = spdk_json_write_begin(print_nvme_cmd, cmd, SPDK_JSON_WRITE_FLAG_FORMATTED);
+	if (w == NULL) {
+		fprintf(stderr, "Unable to allocate json context for printing command.\n");
+		free(dptr_value);
+		return;
+	}
+
+	spdk_json_write_named_object_begin(w, g_nvme_cmd_json_name);
+	spdk_json_write_named_uint32(w, "opc", cmd->opc);
+	spdk_json_write_named_uint32(w, "fuse", cmd->fuse);
+	spdk_json_write_named_uint32(w, "rsvd1", cmd->rsvd1);
+	spdk_json_write_named_uint32(w, "psdt", cmd->psdt);
+	spdk_json_write_named_uint32(w, "cid", cmd->cid);
+	spdk_json_write_named_uint32(w, "nsid", cmd->nsid);
+	spdk_json_write_named_uint32(w, "rsvd2", cmd->rsvd2);
+	spdk_json_write_named_uint32(w, "rsvd3", cmd->rsvd3);
+	spdk_json_write_named_uint32(w, "mptr", cmd->mptr);
+	spdk_json_write_named_string(w, "dptr", dptr_value);
+	spdk_json_write_named_uint32(w, "cdw10", cmd->cdw10);
+	spdk_json_write_named_uint32(w, "cdw11", cmd->cdw11);
+	spdk_json_write_named_uint32(w, "cdw12", cmd->cdw12);
+	spdk_json_write_named_uint32(w, "cdw13", cmd->cdw13);
+	spdk_json_write_named_uint32(w, "cdw14", cmd->cdw14);
+	spdk_json_write_named_uint32(w, "cdw15", cmd->cdw15);
+	spdk_json_write_object_end(w);
+
+	free(dptr_value);
+	spdk_json_write_end(w);
+}
+
+static void
+json_dump_nvme_cmd_list(struct nvme_fuzz_qp *qp)
+{
+	struct nvme_fuzz_request *ctx;
+
+	TAILQ_FOREACH(ctx, &qp->outstanding_ctx_objs, link) {
+		json_dump_nvme_cmd(&ctx->cmd);
+	}
+}
+
+static void
+handle_timeout(struct nvme_fuzz_qp *qp, bool is_admin)
+{
+	fprintf(stderr, "An %s queue has timed out. Dumping all outstanding commands from that queue\n",
+		is_admin ? "Admin" : "I/O");
+	json_dump_nvme_cmd_list(qp);
+	qp->timed_out = true;
+}
+
+static void submit_ns_cmds(struct nvme_fuzz_ns *ns_entry);
+
+static void
+nvme_fuzz_cpl_cb(void *cb_arg, const struct spdk_nvme_cpl *cpl)
+{
+	struct nvme_fuzz_request *ctx = cb_arg;
+	struct nvme_fuzz_qp *qp = ctx->qp;
+
+	qp->completed_cmd_counter++;
+	if (spdk_unlikely(cpl->status.sc == SPDK_NVME_SC_SUCCESS)) {
+		fprintf(stderr, "The following %s command (command num %lu) completed successfully\n",
+			qp->is_admin ? "Admin" : "I/O", qp->completed_cmd_counter);
+		qp->successful_completed_cmd_counter++;
+		json_dump_nvme_cmd(&ctx->cmd);
+
+		if (qp->is_admin) {
+			__sync_bool_compare_and_swap(&g_successful_admin_opcodes[ctx->cmd.opc], false, true);
+		} else {
+			__sync_bool_compare_and_swap(&g_successful_io_opcodes[ctx->cmd.opc], false, true);
+		}
+	} else if (g_verbose_mode == true) {
+		fprintf(stderr, "The following %s command (command num %lu) failed as expected.\n",
+			qp->is_admin ? "Admin" : "I/O", qp->completed_cmd_counter);
+		json_dump_nvme_cmd(&ctx->cmd);
+	}
+
+	qp->timeout_tsc = fuzz_refresh_timeout();
+	TAILQ_REMOVE(&qp->outstanding_ctx_objs, ctx, link);
+	TAILQ_INSERT_HEAD(&qp->free_ctx_objs, ctx, link);
+	assert(qp->num_cmds_outstanding > 0);
+	qp->num_cmds_outstanding--;
+}
+
+static int
+poll_for_completions(void *arg)
+{
+	struct nvme_fuzz_ns *ns_entry = arg;
+	uint64_t current_ticks = spdk_get_ticks();
+	uint64_t *counter;
+	if (!ns_entry->io_qp.timed_out) {
+		spdk_nvme_qpair_process_completions(ns_entry->io_qp.qpair, 0);
+		/* SAlways have to process admin completions for the purposes of keep alive. */
+		spdk_nvme_ctrlr_process_admin_completions(ns_entry->ctrlr);
+	}
+
+	if (g_cmd_array) {
+		if (g_run_admin_commands) {
+			counter = &ns_entry->a_qp.submitted_cmd_counter;
+		} else {
+			counter = &ns_entry->io_qp.submitted_cmd_counter;
+		}
+
+		if (*counter >= g_cmd_array_size) {
+			g_run = false;
+		}
+	} else {
+		if (current_ticks > g_runtime_ticks) {
+			g_run = false;
+		}
+	}
+
+	if (ns_entry->a_qp.timeout_tsc < current_ticks && !ns_entry->a_qp.timed_out &&
+	    ns_entry->a_qp.num_cmds_outstanding > 0) {
+		handle_timeout(&ns_entry->a_qp, true);
+	}
+
+	if (ns_entry->io_qp.timeout_tsc < current_ticks && !ns_entry->io_qp.timed_out &&
+	    ns_entry->io_qp.num_cmds_outstanding > 0) {
+		handle_timeout(&ns_entry->io_qp, false);
+	}
+
+	submit_ns_cmds(ns_entry);
+
+	if (g_run) {
+		return 0;
+	}
+	/*
+	 * We either processed all I/O properly and can shut down normally, or we
+	 * had a qp time out and we need to exit without reducing the values to 0.
+	 */
+	if (ns_entry->io_qp.num_cmds_outstanding == 0 &&
+	    ns_entry->a_qp.num_cmds_outstanding == 0) {
+		goto exit_handler;
+	} else if (ns_entry->io_qp.timed_out && (!g_run_admin_commands || ns_entry->a_qp.timed_out)) {
+		goto exit_handler;
+	} else {
+		return 0;
+	}
+
+exit_handler:
+	spdk_poller_unregister(&ns_entry->req_poller);
+	__sync_sub_and_fetch(&g_num_active_threads, 1);
+	spdk_thread_exit(ns_entry->thread);
+	return 0;
+}
+
+static void
+prep_nvme_cmd(struct nvme_fuzz_ns *ns_entry, struct nvme_fuzz_qp *qp, struct nvme_fuzz_request *ctx)
+{
+	if (g_cmd_array) {
+		memcpy(&ctx->cmd, &g_cmd_array[qp->submitted_cmd_counter], sizeof(ctx->cmd));
+	} else {
+		fuzz_fill_random_bytes((char *)&ctx->cmd, sizeof(ctx->cmd), &qp->random_seed);
+
+		if (g_valid_ns_only) {
+			ctx->cmd.nsid = ns_entry->nsid;
+		}
+	}
+}
+
+static int
+submit_qp_cmds(struct nvme_fuzz_ns *ns, struct nvme_fuzz_qp *qp)
+{
+	struct nvme_fuzz_request *ctx;
+	int rc;
+
+	if (qp->timed_out) {
+		return 0;
+	}
+	/* If we are reading from an array, we need to stop after the last one. */
+	while ((qp->submitted_cmd_counter < g_cmd_array_size || g_cmd_array_size == 0) &&
+	       !TAILQ_EMPTY(&qp->free_ctx_objs)) {
+		ctx = TAILQ_FIRST(&qp->free_ctx_objs);
+		do {
+			prep_nvme_cmd(ns, qp, ctx);
+		} while (qp->is_admin && ctx->cmd.opc == SPDK_NVME_OPC_ASYNC_EVENT_REQUEST);
+
+		TAILQ_REMOVE(&qp->free_ctx_objs, ctx, link);
+		TAILQ_INSERT_HEAD(&qp->outstanding_ctx_objs, ctx, link);
+		qp->num_cmds_outstanding++;
+		qp->submitted_cmd_counter++;
+		if (qp->is_admin) {
+			rc = spdk_nvme_ctrlr_cmd_admin_raw(ns->ctrlr, &ctx->cmd, NULL, 0, nvme_fuzz_cpl_cb, ctx);
+		} else {
+			rc = spdk_nvme_ctrlr_cmd_io_raw(ns->ctrlr, qp->qpair, &ctx->cmd, NULL, 0, nvme_fuzz_cpl_cb, ctx);
+		}
+		if (rc) {
+			return rc;
+		}
+	}
+	return 0;
+}
+
+static void
+submit_ns_cmds(struct nvme_fuzz_ns *ns_entry)
+{
+	int rc;
+
+	if (!g_run) {
+		return;
+	}
+
+	if (g_run_admin_commands) {
+		rc = submit_qp_cmds(ns_entry, &ns_entry->a_qp);
+		if (rc) {
+			goto err_exit;
+		}
+	}
+
+	if (g_cmd_array == NULL || !g_run_admin_commands) {
+		rc = submit_qp_cmds(ns_entry, &ns_entry->io_qp);
+	}
+err_exit:
+	if (rc) {
+		/*
+		 * I see the prospect of having a broken qpair on one ns as interesting
+		 * enough to recommend stopping the application.
+		 */
+		fprintf(stderr, "Unable to submit command with rc %d\n", rc);
+		g_run = false;
+	}
+}
+
+static void
+free_namespaces(void)
+{
+	struct nvme_fuzz_ns *ns, *tmp;
+
+	TAILQ_FOREACH_SAFE(ns, &g_ns_list, tailq, tmp) {
+		printf("NS: %p I/O qp, Total commands completed: %lu, total successful commands: %lu, random_seed: %u\n",
+		       ns->ns,
+		       ns->io_qp.completed_cmd_counter, ns->io_qp.successful_completed_cmd_counter, ns->io_qp.random_seed);
+		printf("NS: %p admin qp, Total commands completed: %lu, total successful commands: %lu, random_seed: %u\n",
+		       ns->ns,
+		       ns->a_qp.completed_cmd_counter, ns->a_qp.successful_completed_cmd_counter, ns->a_qp.random_seed);
+
+		TAILQ_REMOVE(&g_ns_list, ns, tailq);
+		if (ns->io_qp.qpair) {
+			spdk_nvme_ctrlr_free_io_qpair(ns->io_qp.qpair);
+		}
+		if (ns->io_qp.req_ctx) {
+			free(ns->io_qp.req_ctx);
+		}
+		if (ns->a_qp.req_ctx) {
+			free(ns->a_qp.req_ctx);
+		}
+		free(ns);
+	}
+}
+
+static void
+free_controllers(void)
+{
+	struct nvme_fuzz_ctrlr *ctrlr, *tmp;
+
+	TAILQ_FOREACH_SAFE(ctrlr, &g_ctrlr_list, tailq, tmp) {
+		TAILQ_REMOVE(&g_ctrlr_list, ctrlr, tailq);
+		spdk_nvme_detach(ctrlr->ctrlr);
+		free(ctrlr);
+	}
+}
+
+static void
+free_trids(void)
+{
+	struct nvme_fuzz_trid *trid, *tmp;
+
+	TAILQ_FOREACH_SAFE(trid, &g_trid_list, tailq, tmp) {
+		TAILQ_REMOVE(&g_trid_list, trid, tailq);
+		free(trid);
+	}
+}
+
+static void
+register_ns(struct spdk_nvme_ctrlr *ctrlr, struct spdk_nvme_ns *ns, uint32_t nsid)
+{
+	struct nvme_fuzz_ns *ns_entry;
+
+	ns_entry = calloc(1, sizeof(struct nvme_fuzz_ns));
+	if (ns_entry == NULL) {
+		fprintf(stderr, "Unable to allocate an entry for a namespace\n");
+		return;
+	}
+
+	ns_entry->ns = ns;
+	ns_entry->ctrlr = ctrlr;
+	ns_entry->nsid = nsid;
+
+	TAILQ_INIT(&ns_entry->io_qp.free_ctx_objs);
+	TAILQ_INIT(&ns_entry->io_qp.outstanding_ctx_objs);
+	if (g_run_admin_commands) {
+		ns_entry->a_qp.qpair = NULL;
+		TAILQ_INIT(&ns_entry->a_qp.free_ctx_objs);
+		TAILQ_INIT(&ns_entry->a_qp.outstanding_ctx_objs);
+	}
+	TAILQ_INSERT_TAIL(&g_ns_list, ns_entry, tailq);
+}
+
+static void
+register_ctrlr(struct spdk_nvme_ctrlr *ctrlr)
+{
+	struct nvme_fuzz_ctrlr *ctrlr_entry;
+	uint32_t nsid;
+	struct spdk_nvme_ns *ns;
+
+	ctrlr_entry = calloc(1, sizeof(struct nvme_fuzz_ctrlr));
+	if (ctrlr_entry == NULL) {
+		fprintf(stderr, "Unable to allocate an entry for a controller\n");
+		return;
+	}
+
+	ctrlr_entry->ctrlr = ctrlr;
+	TAILQ_INSERT_TAIL(&g_ctrlr_list, ctrlr_entry, tailq);
+
+	for (nsid = spdk_nvme_ctrlr_get_first_active_ns(ctrlr); nsid != 0;
+	     nsid = spdk_nvme_ctrlr_get_next_active_ns(ctrlr, nsid)) {
+		ns = spdk_nvme_ctrlr_get_ns(ctrlr, nsid);
+		if (ns == NULL) {
+			continue;
+		}
+		register_ns(ctrlr, ns, nsid);
+	}
+}
+
+static void
+attach_cb(void *cb_ctx, const struct spdk_nvme_transport_id *trid,
+	  struct spdk_nvme_ctrlr *ctrlr, const struct spdk_nvme_ctrlr_opts *opts)
+{
+	register_ctrlr(ctrlr);
+}
+
+static bool
+probe_cb(void *cb_ctx, const struct spdk_nvme_transport_id *trid, struct spdk_nvme_ctrlr_opts *opts)
+{
+	printf("Controller trtype %s\ttraddr %s\n", spdk_nvme_transport_id_trtype_str(trid->trtype),
+	       trid->traddr);
+
+	return true;
+}
+
+static int
+prep_qpair(struct nvme_fuzz_ns *ns, struct nvme_fuzz_qp *qp, uint32_t max_qdepth)
+{
+	uint32_t i;
+
+	/* ensure that each qpair gets a unique random seed for maximum command dispersion. */
+
+	if (g_seed_value != 0) {
+		qp->random_seed = g_seed_value;
+	} else {
+		/* Take the low 32 bits of spdk_get_ticks. This should be more granular than time(). */
+		qp->random_seed = spdk_get_ticks();
+	}
+
+	qp->timeout_tsc = fuzz_refresh_timeout();
+
+	qp->req_ctx = calloc(max_qdepth, sizeof(struct nvme_fuzz_request));
+	if (qp->req_ctx == NULL) {
+		fprintf(stderr, "Unable to allocate I/O contexts for I/O qpair.\n");
+		return -1;
+	}
+
+	for (i = 0; i < max_qdepth; i++) {
+		qp->req_ctx[i].qp = qp;
+		TAILQ_INSERT_HEAD(&qp->free_ctx_objs, &qp->req_ctx[i], link);
+	}
+
+	return 0;
+}
+
+static int
+prepare_qpairs(void)
+{
+	struct spdk_nvme_io_qpair_opts opts;
+	struct nvme_fuzz_ns *ns_entry;
+
+	TAILQ_FOREACH(ns_entry, &g_ns_list, tailq) {
+		spdk_nvme_ctrlr_get_default_io_qpair_opts(ns_entry->ctrlr, &opts, sizeof(opts));
+		ns_entry->io_qp.qpair = spdk_nvme_ctrlr_alloc_io_qpair(ns_entry->ctrlr, &opts, sizeof(opts));
+		if (ns_entry->io_qp.qpair == NULL) {
+			fprintf(stderr, "Unable to create a qpair for a namespace\n");
+			return -1;
+		}
+
+		ns_entry->io_qp.is_admin = false;
+		if (prep_qpair(ns_entry, &ns_entry->io_qp, g_io_depth) != 0) {
+			fprintf(stderr, "Unable to allocate request contexts for I/O qpair.\n");
+			return -1;
+		}
+
+		if (g_run_admin_commands) {
+			ns_entry->a_qp.is_admin = true;
+			if (prep_qpair(ns_entry, &ns_entry->a_qp, g_admin_depth) != 0) {
+				fprintf(stderr, "Unable to allocate request contexts for admin qpair.\n");
+				return -1;
+			}
+		}
+	}
+	return 0;
+}
+
+static void
+start_ns_poller(void *ctx)
+{
+	struct nvme_fuzz_ns *ns_entry = ctx;
+
+	ns_entry->req_poller = SPDK_POLLER_REGISTER(poll_for_completions, ns_entry, 0);
+	submit_ns_cmds(ns_entry);
+}
+
+static int
+check_app_completion(void *ctx)
+{
+
+	if (g_num_active_threads <= 0) {
+		spdk_poller_unregister(&g_app_completion_poller);
+		if (g_cmd_array) {
+			free(g_cmd_array);
+		}
+		printf("Fuzzing completed. Shutting down the fuzz application\n\n");
+		printf("Dumping successful admin opcodes:\n");
+		report_successful_opcodes(g_successful_admin_opcodes, UNIQUE_OPCODES);
+		printf("Dumping successful io opcodes:\n");
+		report_successful_opcodes(g_successful_io_opcodes, UNIQUE_OPCODES);
+		free_namespaces();
+		free_controllers();
+		free_trids();
+		spdk_app_stop(0);
+	}
+	return 0;
+}
+
+static void
+begin_fuzz(void *ctx)
+{
+	struct nvme_fuzz_ns *ns_entry;
+	struct nvme_fuzz_trid *trid;
+	int rc;
+
+	if (!spdk_iommu_is_enabled()) {
+		/* Don't set rc to an error code here. We don't want to fail an automated test based on this. */
+		fprintf(stderr, "The IOMMU must be enabled to run this program to avoid unsafe memory accesses.\n");
+		rc = 0;
+		goto out;
+	}
+
+	TAILQ_FOREACH(trid, &g_trid_list, tailq) {
+		if (spdk_nvme_probe(&trid->trid, trid, probe_cb, attach_cb, NULL) != 0) {
+			fprintf(stderr, "spdk_nvme_probe() failed for transport address '%s'\n",
+				trid->trid.traddr);
+			rc = -1;
+			goto out;
+		}
+	}
+
+	if (TAILQ_EMPTY(&g_ns_list)) {
+		fprintf(stderr, "No valid NVMe Namespaces to fuzz\n");
+		rc = -EINVAL;
+		goto out;
+	}
+
+	rc = prepare_qpairs();
+
+	if (rc < 0) {
+		fprintf(stderr, "Unable to prepare the qpairs\n");
+		goto out;
+	}
+
+	g_runtime_ticks = spdk_get_ticks() + g_runtime * spdk_get_ticks_hz();
+
+	/* Assigning all of the threads and then starting them makes cleanup easier. */
+	TAILQ_FOREACH(ns_entry, &g_ns_list, tailq) {
+		ns_entry->thread = spdk_thread_create(NULL, NULL);
+		if (ns_entry->thread == NULL) {
+			fprintf(stderr, "Failed to allocate thread for namespace.\n");
+			goto out;
+		}
+	}
+
+	TAILQ_FOREACH(ns_entry, &g_ns_list, tailq) {
+		spdk_thread_send_msg(ns_entry->thread, start_ns_poller, ns_entry);
+		__sync_add_and_fetch(&g_num_active_threads, 1);
+	}
+
+	g_app_completion_poller = SPDK_POLLER_REGISTER(check_app_completion, NULL, 1000000);
+	return;
+out:
+	printf("Shutting down the fuzz application\n");
+	free_namespaces();
+	free_controllers();
+	free_trids();
+	spdk_app_stop(rc);
+}
+
+static int
+parse_trids(void)
+{
+	struct spdk_conf *config = NULL;
+	struct spdk_conf_section *sp;
+	const char *trid_char;
+	struct nvme_fuzz_trid *current_trid;
+	int num_subsystems = 0;
+	int rc = 0;
+
+	if (g_conf_file) {
+		config = spdk_conf_allocate();
+		if (!config) {
+			fprintf(stderr, "Unable to allocate an spdk_conf object\n");
+			return -1;
+		}
+
+		rc = spdk_conf_read(config, g_conf_file);
+		if (rc) {
+			fprintf(stderr, "Unable to convert the conf file into a readable system\n");
+			rc = -1;
+			goto exit;
+		}
+
+		sp = spdk_conf_find_section(config, "Nvme");
+
+		if (sp == NULL) {
+			fprintf(stderr, "No Nvme configuration in conf file\n");
+			goto exit;
+		}
+
+		while ((trid_char = spdk_conf_section_get_nmval(sp, "TransportID", num_subsystems, 0)) != NULL) {
+			current_trid = malloc(sizeof(struct nvme_fuzz_trid));
+			if (!current_trid) {
+				fprintf(stderr, "Unable to allocate memory for transport ID\n");
+				rc = -1;
+				goto exit;
+			}
+			rc = spdk_nvme_transport_id_parse(&current_trid->trid, trid_char);
+
+			if (rc < 0) {
+				fprintf(stderr, "failed to parse transport ID: %s\n", trid_char);
+				free(current_trid);
+				rc = -1;
+				goto exit;
+			}
+			TAILQ_INSERT_TAIL(&g_trid_list, current_trid, tailq);
+			num_subsystems++;
+		}
+	}
+
+exit:
+	if (config != NULL) {
+		spdk_conf_free(config);
+	}
+	return rc;
+}
+
+static void
+nvme_fuzz_usage(void)
+{
+	fprintf(stderr, " -a                        Perform admin commands. if -j is specified, \
+only admin commands will run. Otherwise they will be run in tandem with I/O commands.\n");
+	fprintf(stderr, " -C <path>                 Path to a configuration file.\n");
+	fprintf(stderr,
+		" -j <path>                 Path to a json file containing named objects of type spdk_nvme_cmd. If this option is specified, -t will be ignored.\n");
+	fprintf(stderr, " -N                        Target only valid namespace with commands. \
+This helps dig deeper into other errors besides invalid namespace.\n");
+	fprintf(stderr, " -S <integer>              Seed value for test.\n");
+	fprintf(stderr,
+		" -t <integer>              Time in seconds to run the fuzz test. Only valid if -j is not specified.\n");
+	fprintf(stderr, " -V                        Enable logging of each submitted command.\n");
+}
+
+static int
+nvme_fuzz_parse(int ch, char *arg)
+{
+	int64_t error_test;
+
+	switch (ch) {
+	case 'a':
+		g_run_admin_commands = true;
+		break;
+	case 'C':
+		g_conf_file = optarg;
+		break;
+	case 'j':
+		g_json_file = optarg;
+		break;
+	case 'N':
+		g_valid_ns_only = true;
+		break;
+	case 'S':
+		error_test = spdk_strtol(arg, 10);
+		if (error_test < 0) {
+			fprintf(stderr, "Invalid value supplied for the random seed.\n");
+			return -1;
+		} else {
+			g_seed_value = error_test;
+		}
+		break;
+	case 't':
+		g_runtime = spdk_strtol(optarg, 10);
+		if (g_runtime < 0 || g_runtime > MAX_RUNTIME_S) {
+			fprintf(stderr, "You must supply a positive runtime value less than 86401.\n");
+			return -1;
+		}
+		break;
+	case 'V':
+		g_verbose_mode = true;
+		break;
+	case '?':
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+int
+main(int argc, char **argv)
+{
+	struct spdk_app_opts opts = {};
+	int rc;
+
+	spdk_app_opts_init(&opts);
+	opts.name = "nvme_fuzz";
+
+	g_runtime = DEFAULT_RUNTIME;
+	g_run = true;
+
+	if ((rc = spdk_app_parse_args(argc, argv, &opts, "aC:j:NS:t:V", NULL, nvme_fuzz_parse,
+				      nvme_fuzz_usage) != SPDK_APP_PARSE_ARGS_SUCCESS)) {
+		return rc;
+	}
+
+	if (g_conf_file) {
+		parse_trids();
+	}
+
+	if (g_json_file != NULL) {
+		g_cmd_array_size = fuzz_parse_args_into_array(g_json_file, (void **)&g_cmd_array,
+				   sizeof(struct spdk_nvme_cmd), g_nvme_cmd_json_name, parse_nvme_cmd_obj);
+		if (g_cmd_array_size == 0) {
+			fprintf(stderr, "The provided json file did not contain any valid commands. Exiting.");
+			return -EINVAL;
+		}
+	}
+
+	rc = spdk_app_start(&opts, begin_fuzz, NULL);
+
+	return rc;
+}
diff --git a/src/spdk/test/app/fuzz/vhost_fuzz/.gitignore b/src/spdk/test/app/fuzz/vhost_fuzz/.gitignore
new file mode 100644
index 000000000..2df201f3f
--- /dev/null
+++ b/src/spdk/test/app/fuzz/vhost_fuzz/.gitignore
@@ -0,0 +1 @@
+vhost_fuzz
diff --git a/src/spdk/test/app/fuzz/vhost_fuzz/Makefile b/src/spdk/test/app/fuzz/vhost_fuzz/Makefile
new file mode 100644
index 000000000..69b8d1866
--- /dev/null
+++ b/src/spdk/test/app/fuzz/vhost_fuzz/Makefile
@@ -0,0 +1,42 @@
+#
+#  Copyright (c) Intel Corporation.
+#  All rights reserved.
+#
+#  Redistribution and use in source and binary forms, with or without
+#  modification, are permitted provided that the following conditions
+#  are met:
+#
+#    * Redistributions of source code must retain the above copyright
+#      notice, this list of conditions and the following disclaimer.
+#    * Redistributions in binary form must reproduce the above copyright
+#      notice, this list of conditions and the following disclaimer in
+#      the documentation and/or other materials provided with the
+#      distribution.
+#    * Neither the name of Intel Corporation nor the names of its
+#      contributors may be used to endorse or promote products derived
+#      from this software without specific prior written permission.
+#
+#  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+#  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+#  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+#  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+#  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+#  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+#  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+#  DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+#  THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+#  (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+#  OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+#
+
+SPDK_ROOT_DIR := $(abspath $(CURDIR)/../../../..)
+include $(SPDK_ROOT_DIR)/mk/spdk.common.mk
+
+APP = vhost_fuzz
+
+CFLAGS += -I$(SPDK_ROOT_DIR)/test/app/fuzz/common
+
+C_SRCS := vhost_fuzz_rpc.c vhost_fuzz.c
+
+SPDK_LIB_LIST += event conf json jsonrpc rpc util log sock trace thread virtio
+include $(SPDK_ROOT_DIR)/mk/spdk.app.mk
diff --git a/src/spdk/test/app/fuzz/vhost_fuzz/README.md b/src/spdk/test/app/fuzz/vhost_fuzz/README.md
new file mode 100644
index 000000000..ab9656c5b
--- /dev/null
+++ b/src/spdk/test/app/fuzz/vhost_fuzz/README.md
@@ -0,0 +1,46 @@
+# Overview
+
+This application is intended to fuzz test the SPDK vhost target by supplying
+malformed or invalid requests across a unix domain socket. This fuzzer
+currently supports fuzzing both vhost block and vhost scsi devices. When
+fuzzing a vhost scsi device, users can select whether to fuzz the scsi I/O
+queue or the scsi admin queue. Please see the NVMe fuzzer readme for information
+on how output is generated, debugging procedures, and the JSON format expected
+when supplying preconstructed values to the fuzzer.
+
+# Request Types
+
+Like the NVMe fuzzer, there is an example json file showing the types of requests
+that the application accepts. Since the vhost application accepts both vhost block
+and vhost scsi commands, there are three distinct object types that can be passed in
+to the application.
+
+1. vhost_blk_cmd
+2. vhost_scsi_cmd
+3. vhost_scsi_mgmt_cmd
+
+Each one of these objects contains distinct data types and they should not be used interchangeably.
+
+All three of the data types begin with three iovec structures describing the request, data, and response
+memory locations. By default, these values are overwritten by the application even when supplied as part
+of a json file. This is because the request and resp data pointers are intended to point to portions of
+the data structure.
+
+If you want to override these iovec values using a json file, you can specify the -k option.
+In most cases, this will just result in the application failing all I/O immediately since
+the request will no longer point to a valid memory location.
+
+It is possible to supply all three types of requests in a single array to the application. They will be parsed and
+submitted to the proper block devices.
+
+# RPC
+
+The vhost fuzzer differs from the NVMe fuzzer in that it expects devices to be configured via rpc. The fuzzer should
+always be started with the --wait-for-rpc argument. Please see below for an example of starting the fuzzer.
+
+~~~
+./test/app/fuzz/vhost_fuzz/vhost_fuzz -t 30 --wait-for-rpc &
+./scripts/rpc.py fuzz_vhost_create_dev -s ./Vhost.1 -b -V
+./scripts/rpc.py fuzz_vhost_create_dev -s ./naa.VhostScsi0.1 -l -V
+./scripts/rpc.py framework_start_init
+~~~
diff --git a/src/spdk/test/app/fuzz/vhost_fuzz/example.json b/src/spdk/test/app/fuzz/vhost_fuzz/example.json
new file mode 100644
index 000000000..9157350f8
--- /dev/null
+++ b/src/spdk/test/app/fuzz/vhost_fuzz/example.json
@@ -0,0 +1,95 @@
+{
+  "vhost_scsi_mgmt_cmd": {
+    "req_iov": {
+      "iov_base": "20007960ff60",
+      "iov_len": 51
+    },
+    "data_iov": {
+      "iov_base": "2000794dbe00",
+      "iov_len": 1024
+    },
+    "resp_iov": {
+      "iov_base": "20007960ff98",
+      "iov_len": 108
+    },
+    "lun": "AQA5vBf3KyE=",
+    "tag": 6163879237324549222,
+    "task_attr": 247,
+    "prio": 242,
+    "crn": 169,
+    "cdb": "ErxZ/qpHBau8gPzjbpotpbTnOW/2g0ns2yRh4jhe5kc="
+  },
+  "vhost_scsi_mgmt_cmd": {
+    "req_iov": {
+      "iov_base": "20007960fe78",
+      "iov_len": 51
+    },
+    "data_iov": {
+      "iov_base": "2000794dbe00",
+      "iov_len": 1024
+    },
+    "resp_iov": {
+      "iov_base": "20007960feb0",
+      "iov_len": 108
+    },
+    "lun": "AQAwWRrhAoo=",
+    "tag": 10457151189012466200,
+    "task_attr": 97,
+    "prio": 158,
+    "crn": 41,
+    "cdb": "Ejjxdzl8KwRDhq+MPfY3J3niYfAHj+2irE8Q2vIfQIk="
+  },
+  "vhost_scsi_cmd": {
+    "req_iov": {
+      "iov_base": "20007960fe78",
+      "iov_len": 24
+    },
+    "data_iov": {
+      "iov_base": "20007960fe78",
+      "iov_len": 1024
+    },
+    "resp_iov": {
+      "iov_base": "20007960fe78",
+      "iov_len": 5
+    },
+    "type": 3,
+    "subtype": 872683406,
+    "lun": "LdaLkHOIQxI=",
+    "tag": 8452696012704506104
+  },
+  "vhost_scsi_cmd": {
+    "req_iov": {
+      "iov_base": "20007960fe78",
+      "iov_len": 24
+    },
+    "data_iov": {
+      "iov_base": "20007960fe78",
+      "iov_len": 1024
+    },
+    "resp_iov": {
+      "iov_base": "20007960fe78",
+      "iov_len": 5
+    },
+    "type": 3,
+    "subtype": 872683406,
+    "lun": "LdaLkHOIQxI=",
+    "tag": 8452696012704506104
+  },
+  "vhost_blk_cmd": {
+    "req_iov": {
+      "iov_base": "20007960fe78",
+      "iov_len": 24
+    },
+    "data_iov": {
+      "iov_base": "20007960fe78",
+      "iov_len": 1024
+    },
+    "resp_iov": {
+      "iov_base": "20007960fe78",
+      "iov_len": 5
+    },
+    "type": 2,
+    "ioprio": 4343,
+    "sector": 24323523
+  }
+}
diff --git a/src/spdk/test/app/fuzz/vhost_fuzz/vhost_fuzz.c b/src/spdk/test/app/fuzz/vhost_fuzz/vhost_fuzz.c
new file mode 100644
index 000000000..47dbfbc65
--- /dev/null
+++ b/src/spdk/test/app/fuzz/vhost_fuzz/vhost_fuzz.c
@@ -0,0 +1,1146 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright (c) Intel Corporation. All rights reserved.
+ *   Copyright (c) 2019 Mellanox Technologies LTD. All rights reserved.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following conditions
+ *   are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in
+ *       the documentation and/or other materials provided with the
+ *       distribution.
+ *     * Neither the name of Intel Corporation nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "spdk/stdinc.h"
+#include "spdk/conf.h"
+#include "spdk/env.h"
+#include "spdk/json.h"
+#include "spdk/event.h"
+#include "spdk/likely.h"
+#include "spdk/util.h"
+#include "spdk/string.h"
+#include "spdk_internal/virtio.h"
+#include "spdk_internal/vhost_user.h"
+
+#include "fuzz_common.h"
+#include "vhost_fuzz.h"
+
+#include <linux/virtio_blk.h>
+#include <linux/virtio_scsi.h>
+
+/* Features desired/implemented by virtio blk. */
+#define VIRTIO_BLK_DEV_SUPPORTED_FEATURES		\
+	(1ULL << VIRTIO_BLK_F_BLK_SIZE		|	\
+	 1ULL << VIRTIO_BLK_F_TOPOLOGY		|	\
+	 1ULL << VIRTIO_BLK_F_MQ		|	\
+	 1ULL << VIRTIO_BLK_F_RO		|	\
+	 1ULL << VIRTIO_BLK_F_DISCARD		|	\
+	 1ULL << VIRTIO_RING_F_EVENT_IDX	|	\
+	 1ULL << VHOST_USER_F_PROTOCOL_FEATURES)
+
+/* Features desired/implemented by virtio scsi. */
+#define VIRTIO_SCSI_DEV_SUPPORTED_FEATURES		\
+	(1ULL << VIRTIO_SCSI_F_INOUT		|	\
+	 1ULL << VIRTIO_SCSI_F_HOTPLUG		|	\
+	 1ULL << VIRTIO_RING_F_EVENT_IDX	|	\
+	 1ULL << VHOST_USER_F_PROTOCOL_FEATURES)
+
+#define VIRTIO_DEV_FIXED_QUEUES	2
+#define VIRTIO_SCSI_CONTROLQ	0
+#define VIRTIO_SCSI_EVENTQ	1
+#define VIRTIO_REQUESTQ		2
+#define FUZZ_MAX_QUEUES		3
+
+#define FUZZ_QUEUE_DEPTH	128
+
+#define BLK_IO_NAME		"vhost_blk_cmd"
+#define SCSI_IO_NAME		"vhost_scsi_cmd"
+#define SCSI_MGMT_NAME		"vhost_scsi_mgmt_cmd"
+
+struct fuzz_vhost_iov_ctx {
+	struct iovec			iov_req;
+	struct iovec			iov_data;
+	struct iovec			iov_resp;
+};
+
+struct fuzz_vhost_io_ctx {
+	struct fuzz_vhost_iov_ctx		iovs;
+	union {
+		struct virtio_blk_outhdr	blk_req;
+		struct virtio_scsi_cmd_req	scsi_req;
+		struct virtio_scsi_ctrl_tmf_req	scsi_tmf_req;
+	} req;
+	union {
+		uint8_t					blk_resp;
+		struct virtio_scsi_cmd_resp		scsi_resp;
+		union {
+			struct virtio_scsi_ctrl_tmf_resp	scsi_tmf_resp;
+			struct virtio_scsi_ctrl_an_resp		an_resp;
+		} scsi_tmf_resp;
+	} resp;
+
+	TAILQ_ENTRY(fuzz_vhost_io_ctx) link;
+};
+
+struct fuzz_vhost_dev_ctx {
+	struct virtio_dev			virtio_dev;
+	struct spdk_thread			*thread;
+	struct spdk_poller			*poller;
+
+	struct fuzz_vhost_io_ctx		*io_ctx_array;
+	TAILQ_HEAD(, fuzz_vhost_io_ctx)		free_io_ctx;
+	TAILQ_HEAD(, fuzz_vhost_io_ctx)		outstanding_io_ctx;
+
+	unsigned int				random_seed;
+
+	uint64_t				submitted_io;
+	uint64_t				completed_io;
+	uint64_t				successful_io;
+	uint64_t				timeout_tsc;
+
+	bool					socket_is_blk;
+	bool					test_scsi_tmf;
+	bool					valid_lun;
+	bool					use_bogus_buffer;
+	bool					use_valid_buffer;
+	bool					timed_out;
+
+	TAILQ_ENTRY(fuzz_vhost_dev_ctx)	link;
+};
+
+/* Global run state */
+uint64_t				g_runtime_ticks;
+int					g_runtime;
+int					g_num_active_threads;
+bool					g_run = true;
+bool					g_verbose_mode = false;
+
+/* Global resources */
+TAILQ_HEAD(, fuzz_vhost_dev_ctx)	g_dev_list = TAILQ_HEAD_INITIALIZER(g_dev_list);
+struct spdk_poller			*g_run_poller;
+void					*g_valid_buffer;
+unsigned int				g_random_seed;
+
+
+/* Global parameters and resources for parsed commands */
+bool					g_keep_iov_pointers = false;
+char					*g_json_file = NULL;
+struct fuzz_vhost_io_ctx		*g_blk_cmd_array = NULL;
+struct fuzz_vhost_io_ctx		*g_scsi_cmd_array = NULL;
+struct fuzz_vhost_io_ctx		*g_scsi_mgmt_cmd_array = NULL;
+
+size_t					g_blk_cmd_array_size;
+size_t					g_scsi_cmd_array_size;
+size_t					g_scsi_mgmt_cmd_array_size;
+
+static void
+cleanup(void)
+{
+	struct fuzz_vhost_dev_ctx *dev_ctx, *tmp;
+	printf("Fuzzing completed.\n");
+	TAILQ_FOREACH_SAFE(dev_ctx, &g_dev_list, link, tmp) {
+		printf("device %p stats: Completed I/O: %lu, Successful I/O: %lu\n", dev_ctx,
+		       dev_ctx->completed_io, dev_ctx->successful_io);
+		virtio_dev_release_queue(&dev_ctx->virtio_dev, VIRTIO_REQUESTQ);
+		if (!dev_ctx->socket_is_blk) {
+			virtio_dev_release_queue(&dev_ctx->virtio_dev, VIRTIO_SCSI_EVENTQ);
+			virtio_dev_release_queue(&dev_ctx->virtio_dev, VIRTIO_SCSI_CONTROLQ);
+		}
+		virtio_dev_stop(&dev_ctx->virtio_dev);
+		virtio_dev_destruct(&dev_ctx->virtio_dev);
+		if (dev_ctx->io_ctx_array) {
+			spdk_free(dev_ctx->io_ctx_array);
+		}
+		free(dev_ctx);
+	}
+
+	spdk_free(g_valid_buffer);
+
+	if (g_blk_cmd_array) {
+		free(g_blk_cmd_array);
+	}
+	if (g_scsi_cmd_array) {
+		free(g_scsi_cmd_array);
+	}
+	if (g_scsi_mgmt_cmd_array) {
+		free(g_scsi_mgmt_cmd_array);
+	}
+}
+
+/* Get a memory address that is random and not located in our hugepage memory. */
+static void *
+get_invalid_mem_address(uint64_t length)
+{
+	uint64_t chosen_address = 0x0;
+
+	while (true) {
+		chosen_address = rand();
+		chosen_address = (chosen_address << 32) | rand();
+		if (spdk_vtophys((void *)chosen_address, &length) == SPDK_VTOPHYS_ERROR) {
+			return (void *)chosen_address;
+		}
+	}
+	return NULL;
+}
+
+/* dev initialization code begin. */
+static int
+virtio_dev_init(struct virtio_dev *vdev, const char *socket_path, uint64_t flags,
+		uint16_t max_queues)
+{
+	int rc;
+
+	rc = virtio_user_dev_init(vdev, "dev_ctx", socket_path, 1024);
+	if (rc != 0) {
+		fprintf(stderr, "Failed to initialize virtual bdev\n");
+		return rc;
+	}
+
+	rc = virtio_dev_reset(vdev, flags);
+	if (rc != 0) {
+		return rc;
+	}
+
+	rc = virtio_dev_start(vdev, max_queues, VIRTIO_DEV_FIXED_QUEUES);
+	if (rc != 0) {
+		return rc;
+	}
+
+	rc = virtio_dev_acquire_queue(vdev, VIRTIO_REQUESTQ);
+	if (rc < 0) {
+		fprintf(stderr, "Couldn't get an unused queue for the io_channel.\n");
+		virtio_dev_stop(vdev);
+		return rc;
+	}
+	return 0;
+}
+
+static int
+blk_dev_init(struct virtio_dev *vdev, const char *socket_path, uint16_t max_queues)
+{
+	uint16_t host_max_queues;
+	int rc;
+
+	if (virtio_dev_has_feature(vdev, VIRTIO_BLK_F_MQ)) {
+		rc = virtio_dev_read_dev_config(vdev, offsetof(struct virtio_blk_config, num_queues),
+						&host_max_queues, sizeof(host_max_queues));
+		if (rc) {
+			fprintf(stderr, "%s: config read failed: %s\n", vdev->name, spdk_strerror(-rc));
+			return rc;
+		}
+	} else {
+		host_max_queues = 1;
+	}
+
+	if (max_queues == 0) {
+		fprintf(stderr, "%s: requested 0 request queues (%"PRIu16" available).\n",
+			vdev->name, host_max_queues);
+		return -EINVAL;
+	}
+
+	if (max_queues > host_max_queues) {
+		fprintf(stderr, "%s: requested %"PRIu16" request queues "
+			"but only %"PRIu16" available.\n",
+			vdev->name, max_queues, host_max_queues);
+		max_queues = host_max_queues;
+	}
+
+	return virtio_dev_init(vdev, socket_path, VIRTIO_BLK_DEV_SUPPORTED_FEATURES, max_queues);
+}
+
+static int
+scsi_dev_init(struct virtio_dev *vdev, const char *socket_path, uint16_t max_queues)
+{
+	int rc;
+
+	rc = virtio_dev_init(vdev, socket_path, VIRTIO_SCSI_DEV_SUPPORTED_FEATURES, max_queues);
+	if (rc != 0) {
+		return rc;
+	}
+
+	rc = virtio_dev_acquire_queue(vdev, VIRTIO_SCSI_CONTROLQ);
+	if (rc != 0) {
+		SPDK_ERRLOG("Failed to acquire the controlq.\n");
+		return rc;
+	}
+
+	rc = virtio_dev_acquire_queue(vdev, VIRTIO_SCSI_EVENTQ);
+	if (rc != 0) {
+		SPDK_ERRLOG("Failed to acquire the eventq.\n");
+		virtio_dev_release_queue(vdev, VIRTIO_SCSI_CONTROLQ);
+		return rc;
+	}
+
+	return 0;
+}
+
+int
+fuzz_vhost_dev_init(const char *socket_path, bool is_blk_dev, bool use_bogus_buffer,
+		    bool use_valid_buffer, bool valid_lun, bool test_scsi_tmf)
+{
+	struct fuzz_vhost_dev_ctx *dev_ctx;
+	int rc = 0, i;
+
+	dev_ctx = calloc(1, sizeof(*dev_ctx));
+	if (dev_ctx == NULL) {
+		return -ENOMEM;
+	}
+
+	dev_ctx->socket_is_blk = is_blk_dev;
+	dev_ctx->use_bogus_buffer = use_bogus_buffer;
+	dev_ctx->use_valid_buffer = use_valid_buffer;
+	dev_ctx->valid_lun = valid_lun;
+	dev_ctx->test_scsi_tmf = test_scsi_tmf;
+
+	TAILQ_INIT(&dev_ctx->free_io_ctx);
+	TAILQ_INIT(&dev_ctx->outstanding_io_ctx);
+
+	assert(sizeof(*dev_ctx->io_ctx_array) <= UINT64_MAX / FUZZ_QUEUE_DEPTH);
+	dev_ctx->io_ctx_array = spdk_malloc(sizeof(*dev_ctx->io_ctx_array) * FUZZ_QUEUE_DEPTH, 0x0, NULL,
+					    SPDK_ENV_LCORE_ID_ANY, SPDK_MALLOC_SHARE);
+	if (dev_ctx->io_ctx_array == NULL) {
+		free(dev_ctx);
+		return -ENOMEM;
+	}
+
+	for (i = 0; i < FUZZ_QUEUE_DEPTH; i++) {
+		TAILQ_INSERT_HEAD(&dev_ctx->free_io_ctx, &dev_ctx->io_ctx_array[i], link);
+	}
+
+	dev_ctx->thread = spdk_thread_create(NULL, NULL);
+	if (dev_ctx->thread == NULL) {
+		fprintf(stderr, "Unable to allocate a thread for a fuzz device.\n");
+		rc = -ENOMEM;
+		goto error_out;
+	}
+
+	if (is_blk_dev) {
+		rc = blk_dev_init(&dev_ctx->virtio_dev, socket_path, FUZZ_MAX_QUEUES);
+	} else {
+		rc = scsi_dev_init(&dev_ctx->virtio_dev, socket_path, FUZZ_MAX_QUEUES);
+	}
+
+	if (rc) {
+		fprintf(stderr, "Unable to prepare the device to perform I/O.\n");
+		goto error_out;
+	}
+
+	TAILQ_INSERT_TAIL(&g_dev_list, dev_ctx, link);
+	return 0;
+
+error_out:
+	spdk_free(dev_ctx->io_ctx_array);
+	free(dev_ctx);
+	return rc;
+}
+/* dev initialization code end */
+
+/* data dumping functions begin */
+static int
+dump_virtio_cmd(void *ctx, const void *data, size_t size)
+{
+	fprintf(stderr, "%s\n", (const char *)data);
+	return 0;
+}
+
+static void
+print_blk_io_data(struct spdk_json_write_ctx *w, struct fuzz_vhost_io_ctx *io_ctx)
+{
+	spdk_json_write_named_uint32(w, "type", io_ctx->req.blk_req.type);
+	spdk_json_write_named_uint32(w, "ioprio", io_ctx->req.blk_req.ioprio);
+	spdk_json_write_named_uint64(w, "sector", io_ctx->req.blk_req.sector);
+}
+
+static void
+print_scsi_tmf_io_data(struct spdk_json_write_ctx *w, struct fuzz_vhost_io_ctx *io_ctx)
+{
+	char *lun_data;
+
+	lun_data = fuzz_get_value_base_64_buffer(io_ctx->req.scsi_tmf_req.lun,
+			sizeof(io_ctx->req.scsi_tmf_req.lun));
+
+	spdk_json_write_named_uint32(w, "type", io_ctx->req.scsi_tmf_req.type);
+	spdk_json_write_named_uint32(w, "subtype", io_ctx->req.scsi_tmf_req.subtype);
+	spdk_json_write_named_string(w, "lun", lun_data);
+	spdk_json_write_named_uint64(w, "tag", io_ctx->req.scsi_tmf_req.tag);
+
+	free(lun_data);
+}
+
+static void
+print_scsi_io_data(struct spdk_json_write_ctx *w, struct fuzz_vhost_io_ctx *io_ctx)
+{
+	char *lun_data;
+	char *cdb_data;
+
+	lun_data = fuzz_get_value_base_64_buffer(io_ctx->req.scsi_req.lun,
+			sizeof(io_ctx->req.scsi_req.lun));
+	cdb_data = fuzz_get_value_base_64_buffer(io_ctx->req.scsi_req.cdb,
+			sizeof(io_ctx->req.scsi_req.cdb));
+
+	spdk_json_write_named_string(w, "lun", lun_data);
+	spdk_json_write_named_uint64(w, "tag", io_ctx->req.scsi_req.tag);
+	spdk_json_write_named_uint32(w, "task_attr", io_ctx->req.scsi_req.task_attr);
+	spdk_json_write_named_uint32(w, "prio", io_ctx->req.scsi_req.prio);
+	spdk_json_write_named_uint32(w, "crn", io_ctx->req.scsi_req.crn);
+	spdk_json_write_named_string(w, "cdb", cdb_data);
+
+	free(lun_data);
+	free(cdb_data);
+}
+
+static void
+print_iov_obj(struct spdk_json_write_ctx *w, const char *iov_name, struct iovec *iov)
+{
+	/* "0x" + up to 16 digits + null terminator */
+	char hex_addr[19];
+	int rc;
+
+	rc = snprintf(hex_addr, 19, "%lx", (uintptr_t)iov->iov_base);
+
+	/* default to 0. */
+	if (rc < 0 || rc >= 19) {
+		hex_addr[0] = '0';
+		hex_addr[1] = '\0';
+	}
+
+	spdk_json_write_named_object_begin(w, iov_name);
+	spdk_json_write_named_string(w, "iov_base", hex_addr);
+	spdk_json_write_named_uint64(w, "iov_len", iov->iov_len);
+	spdk_json_write_object_end(w);
+}
+
+static void
+print_iovs(struct spdk_json_write_ctx *w, struct fuzz_vhost_io_ctx *io_ctx)
+{
+	print_iov_obj(w, "req_iov", &io_ctx->iovs.iov_req);
+	print_iov_obj(w, "data_iov", &io_ctx->iovs.iov_data);
+	print_iov_obj(w, "resp_iov", &io_ctx->iovs.iov_resp);
+}
+
+static void
+print_req_obj(struct fuzz_vhost_dev_ctx *dev_ctx, struct fuzz_vhost_io_ctx *io_ctx)
+{
+
+	struct spdk_json_write_ctx *w;
+
+	w = spdk_json_write_begin(dump_virtio_cmd, NULL, SPDK_JSON_WRITE_FLAG_FORMATTED);
+
+	if (dev_ctx->socket_is_blk) {
+		spdk_json_write_named_object_begin(w, BLK_IO_NAME);
+		print_iovs(w, io_ctx);
+		print_blk_io_data(w, io_ctx);
+	} else if (dev_ctx->test_scsi_tmf) {
+		spdk_json_write_named_object_begin(w, SCSI_MGMT_NAME);
+		print_iovs(w, io_ctx);
+		print_scsi_tmf_io_data(w, io_ctx);
+	} else {
+		spdk_json_write_named_object_begin(w, SCSI_IO_NAME);
+		print_iovs(w, io_ctx);
+		print_scsi_io_data(w, io_ctx);
+	}
+	spdk_json_write_object_end(w);
+	spdk_json_write_end(w);
+}
+
+static void
+dump_outstanding_io(struct fuzz_vhost_dev_ctx *dev_ctx)
+{
+	struct fuzz_vhost_io_ctx *io_ctx, *tmp;
+
+	TAILQ_FOREACH_SAFE(io_ctx, &dev_ctx->outstanding_io_ctx, link, tmp) {
+		print_req_obj(dev_ctx, io_ctx);
+		TAILQ_REMOVE(&dev_ctx->outstanding_io_ctx, io_ctx, link);
+		TAILQ_INSERT_TAIL(&dev_ctx->free_io_ctx, io_ctx, link);
+	}
+}
+/* data dumping functions end */
+
+/* data parsing functions begin */
+static int
+hex_value(uint8_t c)
+{
+#define V(x, y) [x] = y + 1
+	static const int8_t val[256] = {
+		V('0', 0), V('1', 1), V('2', 2), V('3', 3), V('4', 4),
+		V('5', 5), V('6', 6), V('7', 7), V('8', 8), V('9', 9),
+		V('A', 0xA), V('B', 0xB), V('C', 0xC), V('D', 0xD), V('E', 0xE), V('F', 0xF),
+		V('a', 0xA), V('b', 0xB), V('c', 0xC), V('d', 0xD), V('e', 0xE), V('f', 0xF),
+	};
+#undef V
+
+	return val[c] - 1;
+}
+
+static int
+fuzz_json_decode_hex_uint64(const struct spdk_json_val *val, void *out)
+{
+	uint64_t *out_val = out;
+	size_t i;
+	char *val_pointer = val->start;
+	int current_val;
+
+	if (val->len > 16) {
+		return -EINVAL;
+	}
+
+	*out_val = 0;
+	for (i = 0; i < val->len; i++) {
+		*out_val = *out_val << 4;
+		current_val = hex_value(*val_pointer);
+		if (current_val < 0) {
+			return -EINVAL;
+		}
+		*out_val += current_val;
+		val_pointer++;
+	}
+
+	return 0;
+}
+
+static const struct spdk_json_object_decoder fuzz_vhost_iov_decoders[] = {
+	{"iov_base", offsetof(struct iovec, iov_base), fuzz_json_decode_hex_uint64},
+	{"iov_len", offsetof(struct iovec, iov_len), spdk_json_decode_uint64},
+};
+
+static size_t
+parse_iov_struct(struct iovec *iovec, struct spdk_json_val *value)
+{
+	int rc;
+
+	if (value->type != SPDK_JSON_VAL_OBJECT_BEGIN) {
+		return -1;
+	}
+
+	rc = spdk_json_decode_object(value,
+				     fuzz_vhost_iov_decoders,
+				     SPDK_COUNTOF(fuzz_vhost_iov_decoders),
+				     iovec);
+	if (rc) {
+		return -1;
+	}
+
+	while (value->type != SPDK_JSON_VAL_OBJECT_END) {
+		value++;
+		rc++;
+	}
+
+	/* The +1 instructs the calling function to skip over the OBJECT_END function. */
+	rc += 1;
+	return rc;
+}
+
+static bool
+parse_vhost_blk_cmds(void *item, struct spdk_json_val *value, size_t num_values)
+{
+	struct fuzz_vhost_io_ctx *io_ctx = item;
+	struct spdk_json_val *prev_value;
+	int nested_object_size;
+	uint64_t tmp_val;
+	size_t i = 0;
+
+	while (i < num_values) {
+		nested_object_size = 1;
+		if (value->type == SPDK_JSON_VAL_NAME) {
+			prev_value = value;
+			value++;
+			i++;
+			if (!strncmp(prev_value->start, "req_iov", prev_value->len)) {
+				nested_object_size = parse_iov_struct(&io_ctx->iovs.iov_req, value);
+			} else if (!strncmp(prev_value->start, "data_iov", prev_value->len)) {
+				nested_object_size = parse_iov_struct(&io_ctx->iovs.iov_data, value);
+			} else if (!strncmp(prev_value->start, "resp_iov", prev_value->len)) {
+				nested_object_size = parse_iov_struct(&io_ctx->iovs.iov_data, value);
+			} else if (!strncmp(prev_value->start, "type", prev_value->len)) {
+				if (fuzz_parse_json_num(value, UINT32_MAX, &tmp_val)) {
+					nested_object_size = -1;
+				} else {
+					io_ctx->req.blk_req.type = tmp_val;
+				}
+			} else if (!strncmp(prev_value->start, "ioprio", prev_value->len)) {
+				if (fuzz_parse_json_num(value, UINT32_MAX, &tmp_val)) {
+					nested_object_size = -1;
+				} else {
+					io_ctx->req.blk_req.ioprio = tmp_val;
+				}
+			} else if (!strncmp(prev_value->start, "sector", prev_value->len)) {
+				if (fuzz_parse_json_num(value, UINT64_MAX, &tmp_val)) {
+					nested_object_size = -1;
+				} else {
+					io_ctx->req.blk_req.sector = tmp_val;
+				}
+			}
+		}
+		if (nested_object_size < 0) {
+			fprintf(stderr, "Invalid value supplied for io_ctx->%.*s: %.*s\n", prev_value->len,
+				(char *)prev_value->start, value->len, (char *)value->start);
+			return false;
+		}
+		value += nested_object_size;
+		i += nested_object_size;
+	}
+	return true;
+}
+
+static bool
+parse_vhost_scsi_cmds(void *item, struct spdk_json_val *value, size_t num_values)
+{
+	struct fuzz_vhost_io_ctx *io_ctx = item;
+	struct spdk_json_val *prev_value;
+	int nested_object_size;
+	uint64_t tmp_val;
+	size_t i = 0;
+
+	while (i < num_values) {
+		nested_object_size = 1;
+		if (value->type == SPDK_JSON_VAL_NAME) {
+			prev_value = value;
+			value++;
+			i++;
+			if (!strncmp(prev_value->start, "req_iov", prev_value->len)) {
+				nested_object_size = parse_iov_struct(&io_ctx->iovs.iov_req, value);
+			} else if (!strncmp(prev_value->start, "data_iov", prev_value->len)) {
+				nested_object_size = parse_iov_struct(&io_ctx->iovs.iov_data, value);
+			} else if (!strncmp(prev_value->start, "resp_iov", prev_value->len)) {
+				nested_object_size = parse_iov_struct(&io_ctx->iovs.iov_data, value);
+			} else if (!strncmp(prev_value->start, "lun", prev_value->len)) {
+				if (fuzz_get_base_64_buffer_value(&io_ctx->req.scsi_req.lun,
+								  sizeof(io_ctx->req.scsi_req.lun),
+								  (char *)value->start,
+								  value->len)) {
+					nested_object_size = -1;
+				}
+			} else if (!strncmp(prev_value->start, "tag", prev_value->len)) {
+				if (fuzz_parse_json_num(value, UINT64_MAX, &tmp_val)) {
+					nested_object_size = -1;
+				} else {
+					io_ctx->req.scsi_req.tag = tmp_val;
+				}
+			} else if (!strncmp(prev_value->start, "task_attr", prev_value->len)) {
+				if (fuzz_parse_json_num(value, UINT8_MAX, &tmp_val)) {
+					nested_object_size = -1;
+				} else {
+					io_ctx->req.scsi_req.task_attr = tmp_val;
+				}
+			} else if (!strncmp(prev_value->start, "prio", prev_value->len)) {
+				if (fuzz_parse_json_num(value, UINT8_MAX, &tmp_val)) {
+					nested_object_size = -1;
+				} else {
+					io_ctx->req.scsi_req.prio = tmp_val;
+				}
+			} else if (!strncmp(prev_value->start, "crn", prev_value->len)) {
+				if (fuzz_parse_json_num(value, UINT8_MAX, &tmp_val)) {
+					nested_object_size = -1;
+				} else {
+					io_ctx->req.scsi_req.crn = tmp_val;
+				}
+			} else if (!strncmp(prev_value->start, "cdb", prev_value->len)) {
+				if (fuzz_get_base_64_buffer_value(&io_ctx->req.scsi_req.cdb,
+								  sizeof(io_ctx->req.scsi_req.cdb),
+								  (char *)value->start,
+								  value->len)) {
+					nested_object_size = -1;
+				}
+			}
+		}
+		if (nested_object_size < 0) {
+			fprintf(stderr, "Invalid value supplied for io_ctx->%.*s: %.*s\n", prev_value->len,
+				(char *)prev_value->start, value->len, (char *)value->start);
+			return false;
+		}
+		value += nested_object_size;
+		i += nested_object_size;
+	}
+	return true;
+
+}
+
+static bool
+parse_vhost_scsi_mgmt_cmds(void *item, struct spdk_json_val *value, size_t num_values)
+{
+	struct fuzz_vhost_io_ctx *io_ctx = item;
+	struct spdk_json_val *prev_value;
+	int nested_object_size;
+	uint64_t tmp_val;
+	size_t i = 0;
+
+	while (i < num_values) {
+		nested_object_size = 1;
+		if (value->type == SPDK_JSON_VAL_NAME) {
+			prev_value = value;
+			value++;
+			i++;
+			if (!strncmp(prev_value->start, "req_iov", prev_value->len)) {
+				nested_object_size = parse_iov_struct(&io_ctx->iovs.iov_req, value);
+			} else if (!strncmp(prev_value->start, "data_iov", prev_value->len)) {
+				nested_object_size = parse_iov_struct(&io_ctx->iovs.iov_data, value);
+			} else if (!strncmp(prev_value->start, "resp_iov", prev_value->len)) {
+				nested_object_size = parse_iov_struct(&io_ctx->iovs.iov_data, value);
+			} else if (!strncmp(prev_value->start, "type", prev_value->len)) {
+				if (fuzz_parse_json_num(value, UINT32_MAX, &tmp_val)) {
+					nested_object_size = -1;
+				} else {
+					io_ctx->req.scsi_tmf_req.type = tmp_val;
+				}
+			} else if (!strncmp(prev_value->start, "subtype", prev_value->len)) {
+				if (fuzz_parse_json_num(value, UINT32_MAX, &tmp_val)) {
+					nested_object_size = -1;
+				} else {
+					io_ctx->req.scsi_tmf_req.subtype = tmp_val;
+				}
+			}  else if (!strncmp(prev_value->start, "lun", prev_value->len)) {
+				if (fuzz_get_base_64_buffer_value(&io_ctx->req.scsi_tmf_req.lun,
+								  sizeof(io_ctx->req.scsi_tmf_req.lun),
+								  (char *)value->start,
+								  value->len)) {
+					nested_object_size = -1;
+				}
+			} else if (!strncmp(prev_value->start, "tag", prev_value->len)) {
+				if (fuzz_parse_json_num(value, UINT64_MAX, &tmp_val)) {
+					nested_object_size = -1;
+				} else {
+					io_ctx->req.scsi_tmf_req.tag = tmp_val;
+				}
+			}
+		}
+		if (nested_object_size < 0) {
+			fprintf(stderr, "Invalid value supplied for io_ctx->%.*s: %.*s\n", prev_value->len,
+				(char *)prev_value->start, value->len, (char *)value->start);
+			return false;
+		}
+		value += nested_object_size;
+		i += nested_object_size;
+	}
+	return true;
+}
+/* data parsing functions end */
+
+/* build requests begin */
+static void
+craft_io_from_array(struct fuzz_vhost_io_ctx *src_ctx, struct fuzz_vhost_io_ctx *dest_ctx)
+{
+	if (g_keep_iov_pointers) {
+		dest_ctx->iovs = src_ctx->iovs;
+	}
+	dest_ctx->req = src_ctx->req;
+}
+
+static void
+craft_virtio_scsi_req(struct fuzz_vhost_dev_ctx *dev_ctx, struct fuzz_vhost_io_ctx *io_ctx)
+{
+	io_ctx->iovs.iov_req.iov_len = sizeof(io_ctx->req.scsi_req);
+	io_ctx->iovs.iov_resp.iov_len = sizeof(io_ctx->resp.scsi_resp);
+	fuzz_fill_random_bytes((char *)&io_ctx->req.scsi_req, sizeof(io_ctx->req.scsi_req),
+			       &dev_ctx->random_seed);
+	/* TODO: set up the logic to find all luns on the target. Right now we are just assuming the first is OK. */
+	if (dev_ctx->valid_lun) {
+		io_ctx->req.scsi_req.lun[0] = 1;
+		io_ctx->req.scsi_req.lun[1] = 0;
+	}
+}
+
+static void
+craft_virtio_scsi_tmf_req(struct fuzz_vhost_dev_ctx *dev_ctx, struct fuzz_vhost_io_ctx *io_ctx)
+{
+	io_ctx->iovs.iov_req.iov_len = sizeof(io_ctx->req.scsi_tmf_req);
+	io_ctx->iovs.iov_resp.iov_len = sizeof(io_ctx->resp.scsi_tmf_resp);
+	fuzz_fill_random_bytes((char *)&io_ctx->req.scsi_tmf_req, sizeof(io_ctx->req.scsi_tmf_req),
+			       &dev_ctx->random_seed);
+	/* TODO: set up the logic to find all luns on the target. Right now we are just assuming the first is OK. */
+	if (dev_ctx->valid_lun) {
+		io_ctx->req.scsi_tmf_req.lun[0] = 1;
+		io_ctx->req.scsi_tmf_req.lun[1] = 0;
+	}
+
+	/* Valid controlqueue commands have to be of type 0, 1, or 2. Any others just return immediately from the target. */
+	/* Try to only test the opcodes that will exercise extra paths in the target side. But allow for at least one invalid value. */
+	io_ctx->req.scsi_tmf_req.type = rand() % 4;
+}
+
+static void
+craft_virtio_blk_req(struct fuzz_vhost_io_ctx *io_ctx)
+{
+	io_ctx->iovs.iov_req.iov_len = sizeof(io_ctx->req.blk_req);
+	io_ctx->iovs.iov_resp.iov_len = sizeof(io_ctx->resp.blk_resp);
+	io_ctx->req.blk_req.type = rand();
+	io_ctx->req.blk_req.sector = rand();
+}
+
+static void
+craft_virtio_req_rsp_pair(struct fuzz_vhost_dev_ctx *dev_ctx, struct fuzz_vhost_io_ctx *io_ctx)
+{
+	struct fuzz_vhost_iov_ctx *iovs = &io_ctx->iovs;
+
+	/*
+	 * Always set these buffer values up front.
+	 * If the user wants to override this with the json values,
+	 * they can specify -k when starting the app. */
+	iovs->iov_req.iov_base = &io_ctx->req;
+	if (dev_ctx->use_bogus_buffer) {
+		iovs->iov_data.iov_len = rand();
+		iovs->iov_data.iov_base = get_invalid_mem_address(iovs->iov_data.iov_len);
+	} else if (dev_ctx->use_valid_buffer) {
+		iovs->iov_data.iov_len = 1024;
+		iovs->iov_data.iov_base = g_valid_buffer;
+	}
+	iovs->iov_resp.iov_base = &io_ctx->resp;
+
+	if (dev_ctx->socket_is_blk && g_blk_cmd_array) {
+		craft_io_from_array(&g_blk_cmd_array[dev_ctx->submitted_io], io_ctx);
+		return;
+	} else if (dev_ctx->test_scsi_tmf && g_scsi_mgmt_cmd_array) {
+		craft_io_from_array(&g_scsi_mgmt_cmd_array[dev_ctx->submitted_io], io_ctx);
+		return;
+	} else if (g_scsi_cmd_array) {
+		craft_io_from_array(&g_scsi_cmd_array[dev_ctx->submitted_io], io_ctx);
+		return;
+	}
+
+	if (dev_ctx->socket_is_blk) {
+		craft_virtio_blk_req(io_ctx);
+	} else if (dev_ctx->test_scsi_tmf) {
+		craft_virtio_scsi_tmf_req(dev_ctx, io_ctx);
+	} else {
+		craft_virtio_scsi_req(dev_ctx, io_ctx);
+	}
+}
+/* build requests end */
+
+/* submit requests begin */
+static uint64_t
+get_max_num_io(struct fuzz_vhost_dev_ctx *dev_ctx)
+{
+	if (dev_ctx->socket_is_blk) {
+		return g_blk_cmd_array_size;
+	} else if (dev_ctx->test_scsi_tmf) {
+		return g_scsi_mgmt_cmd_array_size;
+	} else {
+		return g_scsi_cmd_array_size;
+	}
+}
+
+static int
+submit_virtio_req_rsp_pair(struct fuzz_vhost_dev_ctx *dev_ctx, struct virtqueue *vq,
+			   struct fuzz_vhost_io_ctx *io_ctx)
+{
+	struct fuzz_vhost_iov_ctx *iovs = &io_ctx->iovs;
+	int num_iovs = 2, rc;
+
+	num_iovs += dev_ctx->use_bogus_buffer || dev_ctx->use_valid_buffer ? 1 : 0;
+
+	rc = virtqueue_req_start(vq, io_ctx, num_iovs);
+	if (rc) {
+		return rc;
+	}
+	virtqueue_req_add_iovs(vq, &iovs->iov_req, 1, SPDK_VIRTIO_DESC_RO);
+	/* blk and scsi requests favor different orders for the iov objects. */
+	if (dev_ctx->socket_is_blk) {
+		if (dev_ctx->use_bogus_buffer || dev_ctx->use_valid_buffer) {
+			virtqueue_req_add_iovs(vq, &iovs->iov_data, 1, SPDK_VIRTIO_DESC_WR);
+		}
+		virtqueue_req_add_iovs(vq, &iovs->iov_resp, 1, SPDK_VIRTIO_DESC_WR);
+	} else {
+		virtqueue_req_add_iovs(vq, &iovs->iov_resp, 1, SPDK_VIRTIO_DESC_WR);
+		if (dev_ctx->use_bogus_buffer || dev_ctx->use_valid_buffer) {
+			virtqueue_req_add_iovs(vq, &iovs->iov_data, 1, SPDK_VIRTIO_DESC_WR);
+		}
+	}
+	virtqueue_req_flush(vq);
+	return 0;
+}
+
+static void
+dev_submit_requests(struct fuzz_vhost_dev_ctx *dev_ctx, struct virtqueue *vq,
+		    uint64_t max_io_to_submit)
+{
+	struct fuzz_vhost_io_ctx *io_ctx;
+	int rc;
+
+	while (!TAILQ_EMPTY(&dev_ctx->free_io_ctx) && dev_ctx->submitted_io < max_io_to_submit) {
+		io_ctx = TAILQ_FIRST(&dev_ctx->free_io_ctx);
+		craft_virtio_req_rsp_pair(dev_ctx, io_ctx);
+		rc = submit_virtio_req_rsp_pair(dev_ctx, vq, io_ctx);
+		if (rc == 0) {
+			TAILQ_REMOVE(&dev_ctx->free_io_ctx, io_ctx, link);
+			TAILQ_INSERT_TAIL(&dev_ctx->outstanding_io_ctx, io_ctx, link);
+			dev_ctx->submitted_io++;
+		} else if (rc == -ENOMEM) {
+			/* There are just not enough available buffers right now. try later. */
+			return;
+		} else if (rc == -EINVAL) {
+			/* The virtqueue must be broken. We know we can fit at least three descriptors */
+			fprintf(stderr, "One of the virtqueues for dev %p is broken. stopping all devices.\n", dev_ctx);
+			g_run = 0;
+		}
+	}
+}
+/* submit requests end */
+
+/* complete requests begin */
+static void
+check_successful_op(struct fuzz_vhost_dev_ctx *dev_ctx, struct fuzz_vhost_io_ctx *io_ctx)
+{
+	bool is_successful = false;
+
+	if (dev_ctx->socket_is_blk) {
+		if (io_ctx->resp.blk_resp == 0) {
+			is_successful = true;
+		}
+	} else if (dev_ctx->test_scsi_tmf) {
+		if (io_ctx->resp.scsi_tmf_resp.scsi_tmf_resp.response == 0 &&
+		    io_ctx->resp.scsi_tmf_resp.an_resp.response == 0) {
+			is_successful = true;
+		}
+	} else {
+		if (io_ctx->resp.scsi_resp.status == 0) {
+			is_successful = true;
+		}
+	}
+
+	if (is_successful) {
+		fprintf(stderr, "An I/O completed without an error status. This could be worth looking into.\n");
+		fprintf(stderr,
+			"There is also a good chance that the target just failed before setting a status.\n");
+		dev_ctx->successful_io++;
+		print_req_obj(dev_ctx, io_ctx);
+	} else if (g_verbose_mode) {
+		fprintf(stderr, "The following I/O failed as expected.\n");
+		print_req_obj(dev_ctx, io_ctx);
+	}
+}
+
+static void
+complete_io(struct fuzz_vhost_dev_ctx *dev_ctx, struct fuzz_vhost_io_ctx *io_ctx)
+{
+	TAILQ_REMOVE(&dev_ctx->outstanding_io_ctx, io_ctx, link);
+	TAILQ_INSERT_HEAD(&dev_ctx->free_io_ctx, io_ctx, link);
+	check_successful_op(dev_ctx, io_ctx);
+	dev_ctx->completed_io++;
+	dev_ctx->timeout_tsc = fuzz_refresh_timeout();
+}
+
+static int
+poll_dev(void *ctx)
+{
+	struct fuzz_vhost_dev_ctx *dev_ctx = ctx;
+	struct virtqueue *vq;
+	struct fuzz_vhost_io_ctx *io_ctx[FUZZ_QUEUE_DEPTH];
+	int num_active_threads;
+	uint64_t max_io_to_complete = UINT64_MAX;
+	uint64_t current_ticks;
+	uint32_t len[FUZZ_QUEUE_DEPTH];
+	uint16_t num_cpl, i;
+
+	if (g_json_file) {
+		max_io_to_complete = get_max_num_io(dev_ctx);
+	}
+
+	if (!dev_ctx->socket_is_blk && dev_ctx->test_scsi_tmf) {
+		vq = dev_ctx->virtio_dev.vqs[VIRTIO_SCSI_CONTROLQ];
+	} else {
+		vq = dev_ctx->virtio_dev.vqs[VIRTIO_REQUESTQ];
+	}
+
+	num_cpl = virtio_recv_pkts(vq, (void **)io_ctx, len, FUZZ_QUEUE_DEPTH);
+
+	for (i = 0; i < num_cpl; i++) {
+		complete_io(dev_ctx, io_ctx[i]);
+	}
+
+	current_ticks = spdk_get_ticks();
+
+	if (current_ticks > dev_ctx->timeout_tsc) {
+		dev_ctx->timed_out = true;
+		g_run = false;
+		fprintf(stderr, "The VQ on device %p timed out. Dumping contents now.\n", dev_ctx);
+		dump_outstanding_io(dev_ctx);
+	}
+
+	if (current_ticks > g_runtime_ticks) {
+		g_run = 0;
+	}
+
+	if (!g_run || dev_ctx->completed_io >= max_io_to_complete) {
+		if (TAILQ_EMPTY(&dev_ctx->outstanding_io_ctx)) {
+			spdk_poller_unregister(&dev_ctx->poller);
+			num_active_threads = __sync_sub_and_fetch(&g_num_active_threads, 1);
+			if (num_active_threads == 0) {
+				g_run = 0;
+			}
+			spdk_thread_exit(dev_ctx->thread);
+		}
+		return 0;
+	}
+
+	dev_submit_requests(dev_ctx, vq, max_io_to_complete);
+	return 0;
+}
+/* complete requests end */
+
+static void
+start_io(void *ctx)
+{
+	struct fuzz_vhost_dev_ctx *dev_ctx = ctx;
+
+	if (g_random_seed) {
+		dev_ctx->random_seed = g_random_seed;
+	} else {
+		dev_ctx->random_seed = spdk_get_ticks();
+	}
+
+	dev_ctx->timeout_tsc = fuzz_refresh_timeout();
+
+	dev_ctx->poller = SPDK_POLLER_REGISTER(poll_dev, dev_ctx, 0);
+	if (dev_ctx->poller == NULL) {
+		return;
+	}
+
+}
+
+static int
+end_fuzz(void *ctx)
+{
+	if (!g_run && !g_num_active_threads) {
+		spdk_poller_unregister(&g_run_poller);
+		cleanup();
+		spdk_app_stop(0);
+	}
+	return 0;
+}
+
+static void
+begin_fuzz(void *ctx)
+{
+	struct fuzz_vhost_dev_ctx *dev_ctx;
+
+	g_runtime_ticks = spdk_get_ticks() + spdk_get_ticks_hz() * g_runtime;
+
+	g_valid_buffer = spdk_malloc(0x1000, 0x200, NULL, SPDK_ENV_LCORE_ID_ANY, SPDK_MALLOC_SHARE);
+	if (g_valid_buffer == NULL) {
+		fprintf(stderr, "Failed to allocate a valid buffer for I/O\n");
+		goto out;
+	}
+
+	g_run_poller = SPDK_POLLER_REGISTER(end_fuzz, NULL, 0);
+	if (g_run_poller == NULL) {
+		fprintf(stderr, "Failed to register a poller for test completion checking.\n");
+	}
+
+	TAILQ_FOREACH(dev_ctx, &g_dev_list, link) {
+		assert(dev_ctx->thread != NULL);
+		spdk_thread_send_msg(dev_ctx->thread, start_io, dev_ctx);
+		__sync_add_and_fetch(&g_num_active_threads, 1);
+	}
+
+	return;
+out:
+	cleanup();
+	spdk_app_stop(0);
+}
+
+static void
+fuzz_vhost_usage(void)
+{
+	fprintf(stderr, " -j <path>                 Path to a json file containing named objects.\n");
+	fprintf(stderr,
+		" -k                        Keep the iov pointer addresses from the json file. only valid with -j.\n");
+	fprintf(stderr, " -S <integer>              Seed value for test.\n");
+	fprintf(stderr, " -t <integer>              Time in seconds to run the fuzz test.\n");
+	fprintf(stderr, " -V                        Enable logging of each submitted command.\n");
+}
+
+static int
+fuzz_vhost_parse(int ch, char *arg)
+{
+	int64_t error_test;
+
+	switch (ch) {
+	case 'j':
+		g_json_file = optarg;
+		break;
+	case 'k':
+		g_keep_iov_pointers = true;
+		break;
+	case 'S':
+		error_test = spdk_strtol(arg, 10);
+		if (error_test < 0) {
+			fprintf(stderr, "Invalid value supplied for the random seed.\n");
+			return -1;
+		} else {
+			g_random_seed = spdk_strtol(arg, 10);
+		}
+		break;
+	case 't':
+		g_runtime = spdk_strtol(arg, 10);
+		if (g_runtime < 0 || g_runtime > MAX_RUNTIME_S) {
+			fprintf(stderr, "You must supply a positive runtime value less than 86401.\n");
+			return -1;
+		}
+		break;
+	case 'V':
+		g_verbose_mode = true;
+		break;
+	case '?':
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+int
+main(int argc, char **argv)
+{
+	struct spdk_app_opts opts = {};
+	int rc;
+
+	spdk_app_opts_init(&opts);
+	opts.name = "vhost_fuzz";
+	g_runtime = DEFAULT_RUNTIME;
+
+	rc = spdk_app_parse_args(argc, argv, &opts, "j:kS:t:V", NULL, fuzz_vhost_parse, fuzz_vhost_usage);
+	if (rc != SPDK_APP_PARSE_ARGS_SUCCESS) {
+		fprintf(stderr, "Unable to parse the application arguments.\n");
+		return -1;
+	}
+
+	if (g_json_file != NULL) {
+		g_blk_cmd_array_size = fuzz_parse_args_into_array(g_json_file,
+				       (void **)&g_blk_cmd_array,
+				       sizeof(struct fuzz_vhost_io_ctx),
+				       BLK_IO_NAME, parse_vhost_blk_cmds);
+		g_scsi_cmd_array_size = fuzz_parse_args_into_array(g_json_file,
+					(void **)&g_scsi_cmd_array,
+					sizeof(struct fuzz_vhost_io_ctx),
+					SCSI_IO_NAME, parse_vhost_scsi_cmds);
+		g_scsi_mgmt_cmd_array_size = fuzz_parse_args_into_array(g_json_file,
+					     (void **)&g_scsi_mgmt_cmd_array,
+					     sizeof(struct fuzz_vhost_io_ctx),
+					     SCSI_IO_NAME, parse_vhost_scsi_mgmt_cmds);
+		if (g_blk_cmd_array_size == 0 && g_scsi_cmd_array_size == 0 && g_scsi_mgmt_cmd_array_size == 0) {
+			fprintf(stderr, "The provided json file did not contain any valid commands. Exiting.\n");
+			return -EINVAL;
+		}
+	}
+
+	spdk_app_start(&opts, begin_fuzz, NULL);
+}
diff --git a/src/spdk/test/app/fuzz/vhost_fuzz/vhost_fuzz.h b/src/spdk/test/app/fuzz/vhost_fuzz/vhost_fuzz.h
new file mode 100644
index 000000000..df71a846d
--- /dev/null
+++ b/src/spdk/test/app/fuzz/vhost_fuzz/vhost_fuzz.h
@@ -0,0 +1,41 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright (c) Intel Corporation.
+ *   All rights reserved.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following conditions
+ *   are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in
+ *       the documentation and/or other materials provided with the
+ *       distribution.
+ *     * Neither the name of Intel Corporation nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+
+#ifndef VHOST_FUZZ_H
+#define VHOST_FUZZ_H
+
+int fuzz_vhost_dev_init(const char *socket_path, bool is_blk_dev, bool use_bogus_buffer,
+			bool use_valid_buffer, bool valid_lun, bool test_scsi_tmf);
+
+#endif
diff --git a/src/spdk/test/app/fuzz/vhost_fuzz/vhost_fuzz_rpc.c b/src/spdk/test/app/fuzz/vhost_fuzz/vhost_fuzz_rpc.c
new file mode 100644
index 000000000..b60e3f097
--- /dev/null
+++ b/src/spdk/test/app/fuzz/vhost_fuzz/vhost_fuzz_rpc.c
@@ -0,0 +1,108 @@
+/*-
+ *   BSD LICENSE
+ *
+ *   Copyright (c) Intel Corporation. All rights reserved.
+ *   Copyright (c) 2018 Mellanox Technologies LTD. All rights reserved.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following conditions
+ *   are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in
+ *       the documentation and/or other materials provided with the
+ *       distribution.
+ *     * Neither the name of Intel Corporation nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "spdk/stdinc.h"
+#include "spdk/rpc.h"
+#include "spdk/util.h"
+
+#include "vhost_fuzz.h"
+
+struct rpc_fuzz_vhost_dev_create {
+	char	*socket;
+	bool	is_blk;
+	bool	use_bogus_buffer;
+	bool	use_valid_buffer;
+	bool	valid_lun;
+	bool	test_scsi_tmf;
+};
+
+static const struct spdk_json_object_decoder rpc_fuzz_vhost_dev_create_decoders[] = {
+	{"socket", offsetof(struct rpc_fuzz_vhost_dev_create, socket), spdk_json_decode_string},
+	{"is_blk", offsetof(struct rpc_fuzz_vhost_dev_create, is_blk), spdk_json_decode_bool, true},
+	{"use_bogus_buffer", offsetof(struct rpc_fuzz_vhost_dev_create, use_bogus_buffer), spdk_json_decode_bool, true},
+	{"use_valid_buffer", offsetof(struct rpc_fuzz_vhost_dev_create, use_valid_buffer), spdk_json_decode_bool, true},
+	{"valid_lun", offsetof(struct rpc_fuzz_vhost_dev_create, valid_lun), spdk_json_decode_bool, true},
+	{"test_scsi_tmf", offsetof(struct rpc_fuzz_vhost_dev_create, test_scsi_tmf), spdk_json_decode_bool, true},
+};
+
+static void
+spdk_rpc_fuzz_vhost_create_dev(struct spdk_jsonrpc_request *request,
+			       const struct spdk_json_val *params)
+{
+	struct spdk_json_write_ctx *w;
+	struct rpc_fuzz_vhost_dev_create req = {0};
+	int rc;
+
+	if (spdk_json_decode_object(params, rpc_fuzz_vhost_dev_create_decoders,
+				    SPDK_COUNTOF(rpc_fuzz_vhost_dev_create_decoders), &req)) {
+		fprintf(stderr, "Unable to parse the request.\n");
+		spdk_jsonrpc_send_error_response(request, SPDK_JSONRPC_ERROR_INVALID_PARAMS,
+						 "Unable to parse the object parameters.\n");
+		return;
+	}
+
+	if (strlen(req.socket) > PATH_MAX) {
+		fprintf(stderr, "Socket address is too long.\n");
+		spdk_jsonrpc_send_error_response(request, SPDK_JSONRPC_ERROR_INVALID_PARAMS,
+						 "Unable to parse the object parameters.\n");
+		free(req.socket);
+		return;
+	}
+
+	rc = fuzz_vhost_dev_init(req.socket, req.is_blk, req.use_bogus_buffer, req.use_valid_buffer,
+				 req.valid_lun, req.test_scsi_tmf);
+
+	if (rc != 0) {
+		if (rc == -ENOMEM) {
+			fprintf(stderr, "No valid memory for device initialization.\n");
+			spdk_jsonrpc_send_error_response(request, SPDK_JSONRPC_ERROR_INTERNAL_ERROR,
+							 "No memory returned from host.\n");
+		} else if (rc == -EINVAL) {
+			fprintf(stderr, "Invalid device parameters provided.\n");
+			spdk_jsonrpc_send_error_response(request, SPDK_JSONRPC_ERROR_INVALID_PARAMS,
+							 "Parameters provided were invalid.\n");
+		} else {
+			fprintf(stderr, "unknown error from the guest.\n");
+			spdk_jsonrpc_send_error_response(request, SPDK_JSONRPC_ERROR_INTERNAL_ERROR,
+							 "Unexpected error code.\n");
+		}
+	} else {
+		w = spdk_jsonrpc_begin_result(request);
+		spdk_json_write_bool(w, true);
+		spdk_jsonrpc_end_result(request, w);
+	}
+
+	free(req.socket);
+	return;
+}
+SPDK_RPC_REGISTER("fuzz_vhost_create_dev", spdk_rpc_fuzz_vhost_create_dev, SPDK_RPC_STARTUP);