[PATCH AUTOSEL 5.4 071/330] selftests/bpf: De-flake test_tcpbpf
From: Sasha Levin <sashal@kernel.org>
Date: 2020-09-18 02:02:40
Also in:
lkml, stable
Subsystem:
bpf [general] (safe dynamic programs and tools), bpf [selftests] (test runners & infrastructure), kernel selftest framework, the rest · Maintainers:
Alexei Starovoitov, Daniel Borkmann, Andrii Nakryiko, Eduard Zingerman, Kumar Kartikeya Dwivedi, Shuah Khan, Shuah Khan, Linus Torvalds
From: Stanislav Fomichev <redacted>
[ Upstream commit ef8c84effce3c7a0b8196fcda8f430c815ab511c ]
It looks like BPF program that handles BPF_SOCK_OPS_STATE_CB state
can race with the bpf_map_lookup_elem("global_map"); I sometimes
see the failures in this test and re-running helps.
Since we know that we expect the callback to be called 3 times (one
time for listener socket, two times for both ends of the connection),
let's export this number and add simple retry logic around that.
Also, let's make EXPECT_EQ() not return on failure, but continue
evaluating all conditions; that should make potential debugging
easier.
With this fix in place I don't observe the flakiness anymore.
Signed-off-by: Stanislav Fomichev <redacted>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Cc: Lawrence Brakmo <redacted>
Link: https://lore.kernel.org/bpf/20191204190955.170934-1-sdf@google.com (local)
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
.../selftests/bpf/progs/test_tcpbpf_kern.c | 1 +
tools/testing/selftests/bpf/test_tcpbpf.h | 1 +
.../testing/selftests/bpf/test_tcpbpf_user.c | 25 +++++++++++++------
3 files changed, 20 insertions(+), 7 deletions(-)
diff --git a/tools/testing/selftests/bpf/progs/test_tcpbpf_kern.c b/tools/testing/selftests/bpf/progs/test_tcpbpf_kern.c
index 2e233613d1fc0..7fa4595d2b66b 100644
--- a/tools/testing/selftests/bpf/progs/test_tcpbpf_kern.c
+++ b/tools/testing/selftests/bpf/progs/test_tcpbpf_kern.c@@ -131,6 +131,7 @@ int bpf_testcb(struct bpf_sock_ops *skops) g.bytes_received = skops->bytes_received; g.bytes_acked = skops->bytes_acked; } + g.num_close_events++; bpf_map_update_elem(&global_map, &key, &g, BPF_ANY); }
diff --git a/tools/testing/selftests/bpf/test_tcpbpf.h b/tools/testing/selftests/bpf/test_tcpbpf.h
index 7bcfa62070056..6220b95cbd02c 100644
--- a/tools/testing/selftests/bpf/test_tcpbpf.h
+++ b/tools/testing/selftests/bpf/test_tcpbpf.h@@ -13,5 +13,6 @@ struct tcpbpf_globals { __u64 bytes_received; __u64 bytes_acked; __u32 num_listen; + __u32 num_close_events; }; #endif
diff --git a/tools/testing/selftests/bpf/test_tcpbpf_user.c b/tools/testing/selftests/bpf/test_tcpbpf_user.c
index 716b4e3be5813..3ae127620463d 100644
--- a/tools/testing/selftests/bpf/test_tcpbpf_user.c
+++ b/tools/testing/selftests/bpf/test_tcpbpf_user.c@@ -16,6 +16,9 @@ #include "test_tcpbpf.h" +/* 3 comes from one listening socket + both ends of the connection */ +#define EXPECTED_CLOSE_EVENTS 3 + #define EXPECT_EQ(expected, actual, fmt) \ do { \ if ((expected) != (actual)) { \
@@ -23,13 +26,14 @@ " Actual: %" fmt "\n" \ " Expected: %" fmt "\n", \ (actual), (expected)); \ - goto err; \ + ret--; \ } \ } while (0) int verify_result(const struct tcpbpf_globals *result) { __u32 expected_events; + int ret = 0; expected_events = ((1 << BPF_SOCK_OPS_TIMEOUT_INIT) | (1 << BPF_SOCK_OPS_RWND_INIT) |
@@ -48,15 +52,15 @@ int verify_result(const struct tcpbpf_globals *result) EXPECT_EQ(0x80, result->bad_cb_test_rv, PRIu32); EXPECT_EQ(0, result->good_cb_test_rv, PRIu32); EXPECT_EQ(1, result->num_listen, PRIu32); + EXPECT_EQ(EXPECTED_CLOSE_EVENTS, result->num_close_events, PRIu32); - return 0; -err: - return -1; + return ret; } int verify_sockopt_result(int sock_map_fd) { __u32 key = 0; + int ret = 0; int res; int rv;
@@ -69,9 +73,7 @@ int verify_sockopt_result(int sock_map_fd) rv = bpf_map_lookup_elem(sock_map_fd, &key, &res); EXPECT_EQ(0, rv, "d"); EXPECT_EQ(1, res, "d"); - return 0; -err: - return -1; + return ret; } static int bpf_find_map(const char *test, struct bpf_object *obj,
@@ -96,6 +98,7 @@ int main(int argc, char **argv) int error = EXIT_FAILURE; struct bpf_object *obj; int cg_fd = -1; + int retry = 10; __u32 key = 0; int rv;
@@ -134,12 +137,20 @@ int main(int argc, char **argv) if (sock_map_fd < 0) goto err; +retry_lookup: rv = bpf_map_lookup_elem(map_fd, &key, &g); if (rv != 0) { printf("FAILED: bpf_map_lookup_elem returns %d\n", rv); goto err; } + if (g.num_close_events != EXPECTED_CLOSE_EVENTS && retry--) { + printf("Unexpected number of close events (%d), retrying!\n", + g.num_close_events); + usleep(100); + goto retry_lookup; + } + if (verify_result(&g)) { printf("FAILED: Wrong stats\n"); goto err;
--
2.25.1