Adding upstream version 4.19.249.upstream/4.19.249

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

1 files changed, 435 insertions, 0 deletions

diff --git a/Documentation/fault-injection/fault-injection.txt b/Documentation/fault-injection/fault-injection.txt
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+Fault injection capabilities infrastructure
+===========================================
+
+See also drivers/md/md-faulty.c and "every_nth" module option for scsi_debug.
+
+
+Available fault injection capabilities
+--------------------------------------
+
+o failslab
+
+  injects slab allocation failures. (kmalloc(), kmem_cache_alloc(), ...)
+
+o fail_page_alloc
+
+  injects page allocation failures. (alloc_pages(), get_free_pages(), ...)
+
+o fail_futex
+
+  injects futex deadlock and uaddr fault errors.
+
+o fail_make_request
+
+  injects disk IO errors on devices permitted by setting
+  /sys/block/<device>/make-it-fail or
+  /sys/block/<device>/<partition>/make-it-fail. (generic_make_request())
+
+o fail_mmc_request
+
+  injects MMC data errors on devices permitted by setting
+  debugfs entries under /sys/kernel/debug/mmc0/fail_mmc_request
+
+o fail_function
+
+  injects error return on specific functions, which are marked by
+  ALLOW_ERROR_INJECTION() macro, by setting debugfs entries
+  under /sys/kernel/debug/fail_function. No boot option supported.
+
+o NVMe fault injection
+
+  inject NVMe status code and retry flag on devices permitted by setting
+  debugfs entries under /sys/kernel/debug/nvme*/fault_inject. The default
+  status code is NVME_SC_INVALID_OPCODE with no retry. The status code and
+  retry flag can be set via the debugfs.
+
+
+Configure fault-injection capabilities behavior
+-----------------------------------------------
+
+o debugfs entries
+
+fault-inject-debugfs kernel module provides some debugfs entries for runtime
+configuration of fault-injection capabilities.
+
+- /sys/kernel/debug/fail*/probability:
+
+	likelihood of failure injection, in percent.
+	Format: <percent>
+
+	Note that one-failure-per-hundred is a very high error rate
+	for some testcases.  Consider setting probability=100 and configure
+	/sys/kernel/debug/fail*/interval for such testcases.
+
+- /sys/kernel/debug/fail*/interval:
+
+	specifies the interval between failures, for calls to
+	should_fail() that pass all the other tests.
+
+	Note that if you enable this, by setting interval>1, you will
+	probably want to set probability=100.
+
+- /sys/kernel/debug/fail*/times:
+
+	specifies how many times failures may happen at most.
+	A value of -1 means "no limit".
+
+- /sys/kernel/debug/fail*/space:
+
+	specifies an initial resource "budget", decremented by "size"
+	on each call to should_fail(,size).  Failure injection is
+	suppressed until "space" reaches zero.
+
+- /sys/kernel/debug/fail*/verbose
+
+	Format: { 0 | 1 | 2 }
+	specifies the verbosity of the messages when failure is
+	injected.  '0' means no messages; '1' will print only a single
+	log line per failure; '2' will print a call trace too -- useful
+	to debug the problems revealed by fault injection.
+
+- /sys/kernel/debug/fail*/task-filter:
+
+	Format: { 'Y' | 'N' }
+	A value of 'N' disables filtering by process (default).
+	Any positive value limits failures to only processes indicated by
+	/proc/<pid>/make-it-fail==1.
+
+- /sys/kernel/debug/fail*/require-start:
+- /sys/kernel/debug/fail*/require-end:
+- /sys/kernel/debug/fail*/reject-start:
+- /sys/kernel/debug/fail*/reject-end:
+
+	specifies the range of virtual addresses tested during
+	stacktrace walking.  Failure is injected only if some caller
+	in the walked stacktrace lies within the required range, and
+	none lies within the rejected range.
+	Default required range is [0,ULONG_MAX) (whole of virtual address space).
+	Default rejected range is [0,0).
+
+- /sys/kernel/debug/fail*/stacktrace-depth:
+
+	specifies the maximum stacktrace depth walked during search
+	for a caller within [require-start,require-end) OR
+	[reject-start,reject-end).
+
+- /sys/kernel/debug/fail_page_alloc/ignore-gfp-highmem:
+
+	Format: { 'Y' | 'N' }
+	default is 'N', setting it to 'Y' won't inject failures into
+	highmem/user allocations.
+
+- /sys/kernel/debug/failslab/ignore-gfp-wait:
+- /sys/kernel/debug/fail_page_alloc/ignore-gfp-wait:
+
+	Format: { 'Y' | 'N' }
+	default is 'N', setting it to 'Y' will inject failures
+	only into non-sleep allocations (GFP_ATOMIC allocations).
+
+- /sys/kernel/debug/fail_page_alloc/min-order:
+
+	specifies the minimum page allocation order to be injected
+	failures.
+
+- /sys/kernel/debug/fail_futex/ignore-private:
+
+	Format: { 'Y' | 'N' }
+	default is 'N', setting it to 'Y' will disable failure injections
+	when dealing with private (address space) futexes.
+
+- /sys/kernel/debug/fail_function/inject:
+
+	Format: { 'function-name' | '!function-name' | '' }
+	specifies the target function of error injection by name.
+	If the function name leads '!' prefix, given function is
+	removed from injection list. If nothing specified ('')
+	injection list is cleared.
+
+- /sys/kernel/debug/fail_function/injectable:
+
+	(read only) shows error injectable functions and what type of
+	error values can be specified. The error type will be one of
+	below;
+	- NULL:	retval must be 0.
+	- ERRNO: retval must be -1 to -MAX_ERRNO (-4096).
+	- ERR_NULL: retval must be 0 or -1 to -MAX_ERRNO (-4096).
+
+- /sys/kernel/debug/fail_function/<functiuon-name>/retval:
+
+	specifies the "error" return value to inject to the given
+	function for given function. This will be created when
+	user specifies new injection entry.
+
+o Boot option
+
+In order to inject faults while debugfs is not available (early boot time),
+use the boot option:
+
+	failslab=
+	fail_page_alloc=
+	fail_make_request=
+	fail_futex=
+	mmc_core.fail_request=<interval>,<probability>,<space>,<times>
+
+o proc entries
+
+- /proc/<pid>/fail-nth:
+- /proc/self/task/<tid>/fail-nth:
+
+	Write to this file of integer N makes N-th call in the task fail.
+	Read from this file returns a integer value. A value of '0' indicates
+	that the fault setup with a previous write to this file was injected.
+	A positive integer N indicates that the fault wasn't yet injected.
+	Note that this file enables all types of faults (slab, futex, etc).
+	This setting takes precedence over all other generic debugfs settings
+	like probability, interval, times, etc. But per-capability settings
+	(e.g. fail_futex/ignore-private) take precedence over it.
+
+	This feature is intended for systematic testing of faults in a single
+	system call. See an example below.
+
+How to add new fault injection capability
+-----------------------------------------
+
+o #include <linux/fault-inject.h>
+
+o define the fault attributes
+
+  DECLARE_FAULT_INJECTION(name);
+
+  Please see the definition of struct fault_attr in fault-inject.h
+  for details.
+
+o provide a way to configure fault attributes
+
+- boot option
+
+  If you need to enable the fault injection capability from boot time, you can
+  provide boot option to configure it. There is a helper function for it:
+
+	setup_fault_attr(attr, str);
+
+- debugfs entries
+
+  failslab, fail_page_alloc, and fail_make_request use this way.
+  Helper functions:
+
+	fault_create_debugfs_attr(name, parent, attr);
+
+- module parameters
+
+  If the scope of the fault injection capability is limited to a
+  single kernel module, it is better to provide module parameters to
+  configure the fault attributes.
+
+o add a hook to insert failures
+
+  Upon should_fail() returning true, client code should inject a failure.
+
+	should_fail(attr, size);
+
+Application Examples
+--------------------
+
+o Inject slab allocation failures into module init/exit code
+
+#!/bin/bash
+
+FAILTYPE=failslab
+echo Y > /sys/kernel/debug/$FAILTYPE/task-filter
+echo 10 > /sys/kernel/debug/$FAILTYPE/probability
+echo 100 > /sys/kernel/debug/$FAILTYPE/interval
+echo -1 > /sys/kernel/debug/$FAILTYPE/times
+echo 0 > /sys/kernel/debug/$FAILTYPE/space
+echo 2 > /sys/kernel/debug/$FAILTYPE/verbose
+echo 1 > /sys/kernel/debug/$FAILTYPE/ignore-gfp-wait
+
+faulty_system()
+{
+	bash -c "echo 1 > /proc/self/make-it-fail && exec $*"
+}
+
+if [ $# -eq 0 ]
+then
+	echo "Usage: $0 modulename [ modulename ... ]"
+	exit 1
+fi
+
+for m in $*
+do
+	echo inserting $m...
+	faulty_system modprobe $m
+
+	echo removing $m...
+	faulty_system modprobe -r $m
+done
+
+------------------------------------------------------------------------------
+
+o Inject page allocation failures only for a specific module
+
+#!/bin/bash
+
+FAILTYPE=fail_page_alloc
+module=$1
+
+if [ -z $module ]
+then
+	echo "Usage: $0 <modulename>"
+	exit 1
+fi
+
+modprobe $module
+
+if [ ! -d /sys/module/$module/sections ]
+then
+	echo Module $module is not loaded
+	exit 1
+fi
+
+cat /sys/module/$module/sections/.text > /sys/kernel/debug/$FAILTYPE/require-start
+cat /sys/module/$module/sections/.data > /sys/kernel/debug/$FAILTYPE/require-end
+
+echo N > /sys/kernel/debug/$FAILTYPE/task-filter
+echo 10 > /sys/kernel/debug/$FAILTYPE/probability
+echo 100 > /sys/kernel/debug/$FAILTYPE/interval
+echo -1 > /sys/kernel/debug/$FAILTYPE/times
+echo 0 > /sys/kernel/debug/$FAILTYPE/space
+echo 2 > /sys/kernel/debug/$FAILTYPE/verbose
+echo 1 > /sys/kernel/debug/$FAILTYPE/ignore-gfp-wait
+echo 1 > /sys/kernel/debug/$FAILTYPE/ignore-gfp-highmem
+echo 10 > /sys/kernel/debug/$FAILTYPE/stacktrace-depth
+
+trap "echo 0 > /sys/kernel/debug/$FAILTYPE/probability" SIGINT SIGTERM EXIT
+
+echo "Injecting errors into the module $module... (interrupt to stop)"
+sleep 1000000
+
+------------------------------------------------------------------------------
+
+o Inject open_ctree error while btrfs mount
+
+#!/bin/bash
+
+rm -f testfile.img
+dd if=/dev/zero of=testfile.img bs=1M seek=1000 count=1
+DEVICE=$(losetup --show -f testfile.img)
+mkfs.btrfs -f $DEVICE
+mkdir -p tmpmnt
+
+FAILTYPE=fail_function
+FAILFUNC=open_ctree
+echo $FAILFUNC > /sys/kernel/debug/$FAILTYPE/inject
+echo -12 > /sys/kernel/debug/$FAILTYPE/$FAILFUNC/retval
+echo N > /sys/kernel/debug/$FAILTYPE/task-filter
+echo 100 > /sys/kernel/debug/$FAILTYPE/probability
+echo 0 > /sys/kernel/debug/$FAILTYPE/interval
+echo -1 > /sys/kernel/debug/$FAILTYPE/times
+echo 0 > /sys/kernel/debug/$FAILTYPE/space
+echo 1 > /sys/kernel/debug/$FAILTYPE/verbose
+
+mount -t btrfs $DEVICE tmpmnt
+if [ $? -ne 0 ]
+then
+	echo "SUCCESS!"
+else
+	echo "FAILED!"
+	umount tmpmnt
+fi
+
+echo > /sys/kernel/debug/$FAILTYPE/inject
+
+rmdir tmpmnt
+losetup -d $DEVICE
+rm testfile.img
+
+
+Tool to run command with failslab or fail_page_alloc
+----------------------------------------------------
+In order to make it easier to accomplish the tasks mentioned above, we can use
+tools/testing/fault-injection/failcmd.sh.  Please run a command
+"./tools/testing/fault-injection/failcmd.sh --help" for more information and
+see the following examples.
+
+Examples:
+
+Run a command "make -C tools/testing/selftests/ run_tests" with injecting slab
+allocation failure.
+
+	# ./tools/testing/fault-injection/failcmd.sh \
+		-- make -C tools/testing/selftests/ run_tests
+
+Same as above except to specify 100 times failures at most instead of one time
+at most by default.
+
+	# ./tools/testing/fault-injection/failcmd.sh --times=100 \
+		-- make -C tools/testing/selftests/ run_tests
+
+Same as above except to inject page allocation failure instead of slab
+allocation failure.
+
+	# env FAILCMD_TYPE=fail_page_alloc \
+		./tools/testing/fault-injection/failcmd.sh --times=100 \
+                -- make -C tools/testing/selftests/ run_tests
+
+Systematic faults using fail-nth
+---------------------------------
+
+The following code systematically faults 0-th, 1-st, 2-nd and so on
+capabilities in the socketpair() system call.
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/socket.h>
+#include <sys/syscall.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <errno.h>
+
+int main()
+{
+	int i, err, res, fail_nth, fds[2];
+	char buf[128];
+
+	system("echo N > /sys/kernel/debug/failslab/ignore-gfp-wait");
+	sprintf(buf, "/proc/self/task/%ld/fail-nth", syscall(SYS_gettid));
+	fail_nth = open(buf, O_RDWR);
+	for (i = 1;; i++) {
+		sprintf(buf, "%d", i);
+		write(fail_nth, buf, strlen(buf));
+		res = socketpair(AF_LOCAL, SOCK_STREAM, 0, fds);
+		err = errno;
+		pread(fail_nth, buf, sizeof(buf), 0);
+		if (res == 0) {
+			close(fds[0]);
+			close(fds[1]);
+		}
+		printf("%d-th fault %c: res=%d/%d\n", i, atoi(buf) ? 'N' : 'Y',
+			res, err);
+		if (atoi(buf))
+			break;
+	}
+	return 0;
+}
+
+An example output:
+
+1-th fault Y: res=-1/23
+2-th fault Y: res=-1/23
+3-th fault Y: res=-1/12
+4-th fault Y: res=-1/12
+5-th fault Y: res=-1/23
+6-th fault Y: res=-1/23
+7-th fault Y: res=-1/23
+8-th fault Y: res=-1/12
+9-th fault Y: res=-1/12
+10-th fault Y: res=-1/12
+11-th fault Y: res=-1/12
+12-th fault Y: res=-1/12
+13-th fault Y: res=-1/12
+14-th fault Y: res=-1/12
+15-th fault Y: res=-1/12
+16-th fault N: res=0/12