Commit f67ad87a authored by Stanislav Fomichev's avatar Stanislav Fomichev Committed by Daniel Borkmann

selftests/bpf: retry tests that expect build-id

While running test_progs in a loop I found out that I'm sometimes hitting
"Didn't find expected build ID from the map" error.

Looking at stack_map_get_build_id_offset() it seems that it is racy (by
design) and can sometimes return BPF_STACK_BUILD_ID_IP (i.e. can't trylock
current->mm->mmap_sem).

Let's retry this test a single time.

Fixes: 13790d1c ("bpf: add selftest for stackmap with build_id in NMI context")
Acked-by: 's avatarSong Liu <songliubraving@fb.com>
Signed-off-by: 's avatarStanislav Fomichev <sdf@google.com>
Signed-off-by: 's avatarDaniel Borkmann <daniel@iogearbox.net>
parent 4af396ae
......@@ -1188,7 +1188,9 @@ static void test_stacktrace_build_id(void)
int i, j;
struct bpf_stack_build_id id_offs[PERF_MAX_STACK_DEPTH];
int build_id_matches = 0;
int retry = 1;
retry:
err = bpf_prog_load(file, BPF_PROG_TYPE_TRACEPOINT, &obj, &prog_fd);
if (CHECK(err, "prog_load", "err %d errno %d\n", err, errno))
goto out;
......@@ -1301,6 +1303,19 @@ static void test_stacktrace_build_id(void)
previous_key = key;
} while (bpf_map_get_next_key(stackmap_fd, &previous_key, &key) == 0);
/* stack_map_get_build_id_offset() is racy and sometimes can return
* BPF_STACK_BUILD_ID_IP instead of BPF_STACK_BUILD_ID_VALID;
* try it one more time.
*/
if (build_id_matches < 1 && retry--) {
ioctl(pmu_fd, PERF_EVENT_IOC_DISABLE);
close(pmu_fd);
bpf_object__close(obj);
printf("%s:WARN:Didn't find expected build ID from the map, retrying\n",
__func__);
goto retry;
}
if (CHECK(build_id_matches < 1, "build id match",
"Didn't find expected build ID from the map\n"))
goto disable_pmu;
......@@ -1341,7 +1356,9 @@ static void test_stacktrace_build_id_nmi(void)
int i, j;
struct bpf_stack_build_id id_offs[PERF_MAX_STACK_DEPTH];
int build_id_matches = 0;
int retry = 1;
retry:
err = bpf_prog_load(file, BPF_PROG_TYPE_PERF_EVENT, &obj, &prog_fd);
if (CHECK(err, "prog_load", "err %d errno %d\n", err, errno))
return;
......@@ -1436,6 +1453,19 @@ static void test_stacktrace_build_id_nmi(void)
previous_key = key;
} while (bpf_map_get_next_key(stackmap_fd, &previous_key, &key) == 0);
/* stack_map_get_build_id_offset() is racy and sometimes can return
* BPF_STACK_BUILD_ID_IP instead of BPF_STACK_BUILD_ID_VALID;
* try it one more time.
*/
if (build_id_matches < 1 && retry--) {
ioctl(pmu_fd, PERF_EVENT_IOC_DISABLE);
close(pmu_fd);
bpf_object__close(obj);
printf("%s:WARN:Didn't find expected build ID from the map, retrying\n",
__func__);
goto retry;
}
if (CHECK(build_id_matches < 1, "build id match",
"Didn't find expected build ID from the map\n"))
goto disable_pmu;
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment