1 files changed, 102 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/test_get_stack_rawtp.c b/tools/testing/selftests/bpf/progs/test_get_stack_rawtp.c
new file mode 100644
index 000000000..b6a6eb279
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_get_stack_rawtp.c
@@ -0,0 +1,102 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+
+/* Permit pretty deep stack traces */
+#define MAX_STACK_RAWTP 100
+struct stack_trace_t {
+	int pid;
+	int kern_stack_size;
+	int user_stack_size;
+	int user_stack_buildid_size;
+	__u64 kern_stack[MAX_STACK_RAWTP];
+	__u64 user_stack[MAX_STACK_RAWTP];
+	struct bpf_stack_build_id user_stack_buildid[MAX_STACK_RAWTP];
+};
+
+struct {
+	__uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
+	__uint(max_entries, 2);
+	__uint(key_size, sizeof(int));
+	__uint(value_size, sizeof(__u32));
+} perfmap SEC(".maps");
+
+struct {
+	__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
+	__uint(max_entries, 1);
+	__type(key, __u32);
+	__type(value, struct stack_trace_t);
+} stackdata_map SEC(".maps");
+
+/* Allocate per-cpu space twice the needed. For the code below
+ *   usize = bpf_get_stack(ctx, raw_data, max_len, BPF_F_USER_STACK);
+ *   if (usize < 0)
+ *     return 0;
+ *   ksize = bpf_get_stack(ctx, raw_data + usize, max_len - usize, 0);
+ *
+ * If we have value_size = MAX_STACK_RAWTP * sizeof(__u64),
+ * verifier will complain that access "raw_data + usize"
+ * with size "max_len - usize" may be out of bound.
+ * The maximum "raw_data + usize" is "raw_data + max_len"
+ * and the maximum "max_len - usize" is "max_len", verifier
+ * concludes that the maximum buffer access range is
+ * "raw_data[0...max_len * 2 - 1]" and hence reject the program.
+ *
+ * Doubling the to-be-used max buffer size can fix this verifier
+ * issue and avoid complicated C programming massaging.
+ * This is an acceptable workaround since there is one entry here.
+ */
+struct {
+	__uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
+	__uint(max_entries, 1);
+	__type(key, __u32);
+	__type(value, __u64[2 * MAX_STACK_RAWTP]);
+} rawdata_map SEC(".maps");
+
+SEC("raw_tracepoint/sys_enter")
+int bpf_prog1(void *ctx)
+{
+	int max_len, max_buildid_len, total_size;
+	struct stack_trace_t *data;
+	long usize, ksize;
+	void *raw_data;
+	__u32 key = 0;
+
+	data = bpf_map_lookup_elem(&stackdata_map, &key);
+	if (!data)
+		return 0;
+
+	max_len = MAX_STACK_RAWTP * sizeof(__u64);
+	max_buildid_len = MAX_STACK_RAWTP * sizeof(struct bpf_stack_build_id);
+	data->pid = bpf_get_current_pid_tgid();
+	data->kern_stack_size = bpf_get_stack(ctx, data->kern_stack,
+					      max_len, 0);
+	data->user_stack_size = bpf_get_stack(ctx, data->user_stack, max_len,
+					    BPF_F_USER_STACK);
+	data->user_stack_buildid_size = bpf_get_stack(
+		ctx, data->user_stack_buildid, max_buildid_len,
+		BPF_F_USER_STACK | BPF_F_USER_BUILD_ID);
+	bpf_perf_event_output(ctx, &perfmap, 0, data, sizeof(*data));
+
+	/* write both kernel and user stacks to the same buffer */
+	raw_data = bpf_map_lookup_elem(&rawdata_map, &key);
+	if (!raw_data)
+		return 0;
+
+	usize = bpf_get_stack(ctx, raw_data, max_len, BPF_F_USER_STACK);
+	if (usize < 0)
+		return 0;
+
+	ksize = bpf_get_stack(ctx, raw_data + usize, max_len - usize, 0);
+	if (ksize < 0)
+		return 0;
+
+	total_size = usize + ksize;
+	if (total_size > 0 && total_size <= max_len)
+		bpf_perf_event_output(ctx, &perfmap, 0, raw_data, total_size);
+
+	return 0;
+}
+
+char _license[] SEC("license") = "GPL";