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authorStanislav Fomichev <sdf@google.com>2019-01-16 14:03:17 -0800
committerDaniel Borkmann <daniel@iogearbox.net>2019-01-17 16:43:18 +0100
commitf67ad87ab3120e82845521b18a2b99273a340308 (patch)
tree051b55414a98c357d5e0e948f8fc9d55e3acd095
parent4af396ae4836c4ecab61e975b8e61270c551894d (diff)
download96b-common-f67ad87ab3120e82845521b18a2b99273a340308.tar.gz
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: 13790d1cc72c ("bpf: add selftest for stackmap with build_id in NMI context") Acked-by: Song Liu <songliubraving@fb.com> Signed-off-by: Stanislav Fomichev <sdf@google.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
-rw-r--r--tools/testing/selftests/bpf/test_progs.c30
1 files changed, 30 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c
index 126fc624290d..25f0083a9b2e 100644
--- a/tools/testing/selftests/bpf/test_progs.c
+++ b/tools/testing/selftests/bpf/test_progs.c
@@ -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;