From: Geliang Tang tanggeliang@kylinos.cn
Run bpf_tcp_ca selftests (./test_progs -t bpf_tcp_ca) on a Loongarch platform, some "Segmentation fault" errors occur:
''' test_dctcp:PASS:bpf_dctcp__open_and_load 0 nsec test_dctcp:FAIL:bpf_map__attach_struct_ops unexpected error: -524 #29/1 bpf_tcp_ca/dctcp:FAIL test_cubic:PASS:bpf_cubic__open_and_load 0 nsec test_cubic:FAIL:bpf_map__attach_struct_ops unexpected error: -524 #29/2 bpf_tcp_ca/cubic:FAIL test_dctcp_fallback:PASS:dctcp_skel 0 nsec test_dctcp_fallback:PASS:bpf_dctcp__load 0 nsec test_dctcp_fallback:FAIL:dctcp link unexpected error: -524 #29/4 bpf_tcp_ca/dctcp_fallback:FAIL test_write_sk_pacing:PASS:open_and_load 0 nsec test_write_sk_pacing:FAIL:attach_struct_ops unexpected error: -524 #29/6 bpf_tcp_ca/write_sk_pacing:FAIL test_update_ca:PASS:open 0 nsec test_update_ca:FAIL:attach_struct_ops unexpected error: -524 settcpca:FAIL:setsockopt unexpected setsockopt: \ actual -1 == expected -1 (network_helpers.c:99: errno: No such file or directory) \ Failed to call post_socket_cb start_test:FAIL:start_server_str unexpected start_server_str: \ actual -1 == expected -1 test_update_ca:FAIL:ca1_ca1_cnt unexpected ca1_ca1_cnt: \ actual 0 <= expected 0 #29/9 bpf_tcp_ca/update_ca:FAIL #29 bpf_tcp_ca:FAIL Caught signal #11! Stack trace: ./test_progs(crash_handler+0x28)[0x5555567ed91c] linux-vdso.so.1(__vdso_rt_sigreturn+0x0)[0x7ffffee408b0] ./test_progs(bpf_link__update_map+0x80)[0x555556824a78] ./test_progs(+0x94d68)[0x5555564c4d68] ./test_progs(test_bpf_tcp_ca+0xe8)[0x5555564c6a88] ./test_progs(+0x3bde54)[0x5555567ede54] ./test_progs(main+0x61c)[0x5555567efd54] /usr/lib64/libc.so.6(+0x22208)[0x7ffff2aaa208] /usr/lib64/libc.so.6(__libc_start_main+0xac)[0x7ffff2aaa30c] ./test_progs(_start+0x48)[0x55555646bca8] Segmentation fault '''
This is because "link" returned by bpf_map__attach_struct_ops() is NULL in this case. test_progs crashs when this NULL link passes to bpf_link__update_map(). This patch adds NULL checks for all links in bpf_tcp_ca to fix these errors. If "link" is NULL, goto the newly added label "err" to destroy the skel.
v2: - use "goto err" instead of "return" as Eduard suggested.
Signed-off-by: Geliang Tang tanggeliang@kylinos.cn --- .../selftests/bpf/prog_tests/bpf_tcp_ca.c | 16 ++++++++++++---- 1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c b/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c index 5909c1f82f3b..9effdfb1a5ce 100644 --- a/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c +++ b/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c @@ -407,7 +407,8 @@ static void test_update_ca(void) return;
link = bpf_map__attach_struct_ops(skel->maps.ca_update_1); - ASSERT_OK_PTR(link, "attach_struct_ops"); + if (!ASSERT_OK_PTR(link, "attach_struct_ops")) + goto err;
do_test(&opts); saved_ca1_cnt = skel->bss->ca1_cnt; @@ -421,6 +422,7 @@ static void test_update_ca(void) ASSERT_GT(skel->bss->ca2_cnt, 0, "ca2_ca2_cnt");
bpf_link__destroy(link); +err: tcp_ca_update__destroy(skel); }
@@ -443,7 +445,8 @@ static void test_update_wrong(void) return;
link = bpf_map__attach_struct_ops(skel->maps.ca_update_1); - ASSERT_OK_PTR(link, "attach_struct_ops"); + if (!ASSERT_OK_PTR(link, "attach_struct_ops")) + goto err;
do_test(&opts); saved_ca1_cnt = skel->bss->ca1_cnt; @@ -456,6 +459,7 @@ static void test_update_wrong(void) ASSERT_GT(skel->bss->ca1_cnt, saved_ca1_cnt, "ca2_ca1_cnt");
bpf_link__destroy(link); +err: tcp_ca_update__destroy(skel); }
@@ -480,7 +484,8 @@ static void test_mixed_links(void) ASSERT_OK_PTR(link_nl, "attach_struct_ops_nl");
link = bpf_map__attach_struct_ops(skel->maps.ca_update_1); - ASSERT_OK_PTR(link, "attach_struct_ops"); + if (!ASSERT_OK_PTR(link, "attach_struct_ops")) + goto err;
do_test(&opts); ASSERT_GT(skel->bss->ca1_cnt, 0, "ca1_ca1_cnt"); @@ -489,6 +494,7 @@ static void test_mixed_links(void) ASSERT_ERR(err, "update_map");
bpf_link__destroy(link); +err: bpf_link__destroy(link_nl); tcp_ca_update__destroy(skel); } @@ -532,7 +538,8 @@ static void test_link_replace(void) bpf_link__destroy(link);
link = bpf_map__attach_struct_ops(skel->maps.ca_update_2); - ASSERT_OK_PTR(link, "attach_struct_ops_2nd"); + if (!ASSERT_OK_PTR(link, "attach_struct_ops_2nd")) + goto err;
/* BPF_F_REPLACE with a wrong old map Fd. It should fail! * @@ -555,6 +562,7 @@ static void test_link_replace(void)
bpf_link__destroy(link);
+err: tcp_ca_update__destroy(skel); }