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Commit 79b45350 authored by Yonghong Song's avatar Yonghong Song Committed by Alexei Starovoitov
Browse files

tools/bpf: add a test for bpf_get_stack with tracepoint prog 



The test_stacktrace_map and test_stacktrace_build_id are
enhanced to call bpf_get_stack in the helper to get the
stack trace as well.  The stack traces from bpf_get_stack
and bpf_get_stackid are compared to ensure that for the
same stack as represented as the same hash, their ip addresses
or build id's must be the same.

Acked-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarYonghong Song <yhs@fb.com>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 173965fb

tools/testing/selftests/bpf/test_progs.c

+64 −6
Original line number Diff line number Diff line
@@ -906,11 +906,47 @@ static int compare_map_keys(int map1_fd, int map2_fd) 
	return 0;

}



static int compare_stack_ips(int smap_fd, int amap_fd, int stack_trace_len)

{

	__u32 key, next_key, *cur_key_p, *next_key_p;

	char *val_buf1, *val_buf2;

	int i, err = 0;



	val_buf1 = malloc(stack_trace_len);

	val_buf2 = malloc(stack_trace_len);

	cur_key_p = NULL;

	next_key_p = &key;

	while (bpf_map_get_next_key(smap_fd, cur_key_p, next_key_p) == 0) {

		err = bpf_map_lookup_elem(smap_fd, next_key_p, val_buf1);

		if (err)

			goto out;

		err = bpf_map_lookup_elem(amap_fd, next_key_p, val_buf2);

		if (err)

			goto out;

		for (i = 0; i < stack_trace_len; i++) {

			if (val_buf1[i] != val_buf2[i]) {

				err = -1;

				goto out;

			}

		}

		key = *next_key_p;

		cur_key_p = &key;

		next_key_p = &next_key;

	}

	if (errno != ENOENT)

		err = -1;



out:

	free(val_buf1);

	free(val_buf2);

	return err;

}



static void test_stacktrace_map()

{

	int control_map_fd, stackid_hmap_fd, stackmap_fd;

	int control_map_fd, stackid_hmap_fd, stackmap_fd, stack_amap_fd;

	const char *file = "./test_stacktrace_map.o";

	int bytes, efd, err, pmu_fd, prog_fd;

	int bytes, efd, err, pmu_fd, prog_fd, stack_trace_len;

	struct perf_event_attr attr = {};

	__u32 key, val, duration = 0;

	struct bpf_object *obj;
@@ -966,6 +1002,10 @@ static void test_stacktrace_map() 
	if (stackmap_fd < 0)

		goto disable_pmu;



	stack_amap_fd = bpf_find_map(__func__, obj, "stack_amap");

	if (stack_amap_fd < 0)

		goto disable_pmu;



	/* give some time for bpf program run */

	sleep(1);
@@ -987,6 +1027,12 @@ static void test_stacktrace_map() 
		  "err %d errno %d\n", err, errno))

		goto disable_pmu_noerr;



	stack_trace_len = PERF_MAX_STACK_DEPTH * sizeof(__u64);

	err = compare_stack_ips(stackmap_fd, stack_amap_fd, stack_trace_len);

	if (CHECK(err, "compare_stack_ips stackmap vs. stack_amap",

		  "err %d errno %d\n", err, errno))

		goto disable_pmu_noerr;



	goto disable_pmu_noerr;

disable_pmu:

	error_cnt++;
@@ -1080,9 +1126,9 @@ static int extract_build_id(char *build_id, size_t size) 


static void test_stacktrace_build_id(void)

{

	int control_map_fd, stackid_hmap_fd, stackmap_fd;

	int control_map_fd, stackid_hmap_fd, stackmap_fd, stack_amap_fd;

	const char *file = "./test_stacktrace_build_id.o";

	int bytes, efd, err, pmu_fd, prog_fd;

	int bytes, efd, err, pmu_fd, prog_fd, stack_trace_len;

	struct perf_event_attr attr = {};

	__u32 key, previous_key, val, duration = 0;

	struct bpf_object *obj;
@@ -1147,6 +1193,11 @@ static void test_stacktrace_build_id(void) 
		  err, errno))

		goto disable_pmu;



	stack_amap_fd = bpf_find_map(__func__, obj, "stack_amap");

	if (CHECK(stack_amap_fd < 0, "bpf_find_map stack_amap",

		  "err %d errno %d\n", err, errno))

		goto disable_pmu;



	assert(system("dd if=/dev/urandom of=/dev/zero count=4 2> /dev/null")

	       == 0);

	assert(system("./urandom_read if=/dev/urandom of=/dev/zero count=4 2> /dev/null") == 0);
@@ -1198,8 +1249,15 @@ static void test_stacktrace_build_id(void) 
		previous_key = key;

	} while (bpf_map_get_next_key(stackmap_fd, &previous_key, &key) == 0);



	CHECK(build_id_matches < 1, "build id match",

	      "Didn't find expected build ID from the map");

	if (CHECK(build_id_matches < 1, "build id match",

		  "Didn't find expected build ID from the map"))

		goto disable_pmu;



	stack_trace_len = PERF_MAX_STACK_DEPTH

		* sizeof(struct bpf_stack_build_id);

	err = compare_stack_ips(stackmap_fd, stack_amap_fd, stack_trace_len);

	CHECK(err, "compare_stack_ips stackmap vs. stack_amap",

	      "err %d errno %d\n", err, errno);



disable_pmu:

	ioctl(pmu_fd, PERF_EVENT_IOC_DISABLE);

tools/testing/selftests/bpf/test_stacktrace_build_id.c

+18 −2
Original line number Diff line number Diff line
@@ -19,7 +19,7 @@ struct bpf_map_def SEC("maps") stackid_hmap = { 
	.type = BPF_MAP_TYPE_HASH,

	.key_size = sizeof(__u32),

	.value_size = sizeof(__u32),

	.max_entries = 10000,

	.max_entries = 16384,

};



struct bpf_map_def SEC("maps") stackmap = {
@@ -31,6 +31,14 @@ struct bpf_map_def SEC("maps") stackmap = { 
	.map_flags = BPF_F_STACK_BUILD_ID,

};



struct bpf_map_def SEC("maps") stack_amap = {

	.type = BPF_MAP_TYPE_ARRAY,

	.key_size = sizeof(__u32),

	.value_size = sizeof(struct bpf_stack_build_id)

		* PERF_MAX_STACK_DEPTH,

	.max_entries = 128,

};



/* taken from /sys/kernel/debug/tracing/events/random/urandom_read/format */

struct random_urandom_args {

	unsigned long long pad;
@@ -42,7 +50,10 @@ struct random_urandom_args { 
SEC("tracepoint/random/urandom_read")

int oncpu(struct random_urandom_args *args)

{

	__u32 max_len = sizeof(struct bpf_stack_build_id)

			* PERF_MAX_STACK_DEPTH;

	__u32 key = 0, val = 0, *value_p;

	void *stack_p;



	value_p = bpf_map_lookup_elem(&control_map, &key);

	if (value_p && *value_p)
@@ -50,8 +61,13 @@ int oncpu(struct random_urandom_args *args) 


	/* The size of stackmap and stackid_hmap should be the same */

	key = bpf_get_stackid(args, &stackmap, BPF_F_USER_STACK);

	if ((int)key >= 0)

	if ((int)key >= 0) {

		bpf_map_update_elem(&stackid_hmap, &key, &val, 0);

		stack_p = bpf_map_lookup_elem(&stack_amap, &key);

		if (stack_p)

			bpf_get_stack(args, stack_p, max_len,

				      BPF_F_USER_STACK | BPF_F_USER_BUILD_ID);

	}



	return 0;

}

tools/testing/selftests/bpf/test_stacktrace_map.c

+16 −3
Original line number Diff line number Diff line
@@ -19,14 +19,21 @@ struct bpf_map_def SEC("maps") stackid_hmap = { 
	.type = BPF_MAP_TYPE_HASH,

	.key_size = sizeof(__u32),

	.value_size = sizeof(__u32),

	.max_entries = 10000,

	.max_entries = 16384,

};



struct bpf_map_def SEC("maps") stackmap = {

	.type = BPF_MAP_TYPE_STACK_TRACE,

	.key_size = sizeof(__u32),

	.value_size = sizeof(__u64) * PERF_MAX_STACK_DEPTH,

	.max_entries = 10000,

	.max_entries = 16384,

};



struct bpf_map_def SEC("maps") stack_amap = {

	.type = BPF_MAP_TYPE_ARRAY,

	.key_size = sizeof(__u32),

	.value_size = sizeof(__u64) * PERF_MAX_STACK_DEPTH,

	.max_entries = 16384,

};



/* taken from /sys/kernel/debug/tracing/events/sched/sched_switch/format */
@@ -44,7 +51,9 @@ struct sched_switch_args { 
SEC("tracepoint/sched/sched_switch")

int oncpu(struct sched_switch_args *ctx)

{

	__u32 max_len = PERF_MAX_STACK_DEPTH * sizeof(__u64);

	__u32 key = 0, val = 0, *value_p;

	void *stack_p;



	value_p = bpf_map_lookup_elem(&control_map, &key);

	if (value_p && *value_p)
@@ -52,8 +61,12 @@ int oncpu(struct sched_switch_args *ctx) 


	/* The size of stackmap and stackid_hmap should be the same */

	key = bpf_get_stackid(ctx, &stackmap, 0);

	if ((int)key >= 0)

	if ((int)key >= 0) {

		bpf_map_update_elem(&stackid_hmap, &key, &val, 0);

		stack_p = bpf_map_lookup_elem(&stack_amap, &key);

		if (stack_p)

			bpf_get_stack(ctx, stack_p, max_len, 0);

	}



	return 0;

}