[PATCH AUTOSEL 5.18 17/53] selftests/bpf: Shuffle cookies symbols in kprobe multi test

From: Sasha Levin
Date: Mon Jun 27 2022 - 22:20:01 EST


From: Jiri Olsa <jolsa@xxxxxxxxxx>

[ Upstream commit ad8848535e97f4a5374fc68f7a5d16e2565940cc ]

There's a kernel bug that causes cookies to be misplaced and
the reason we did not catch this with this test is that we
provide bpf_fentry_test* functions already sorted by name.

Shuffling function bpf_fentry_test2 deeper in the list and
keeping the current cookie values as before will trigger
the bug.

The kernel fix is coming in following changes.

Acked-by: Song Liu <songliubraving@xxxxxx>
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20220615112118.497303-2-jolsa@xxxxxxxxxx
Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
.../selftests/bpf/prog_tests/bpf_cookie.c | 78 +++++++++----------
.../selftests/bpf/progs/kprobe_multi.c | 24 +++---
2 files changed, 51 insertions(+), 51 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c b/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c
index 923a6139b2d8..aebbbb8f983f 100644
--- a/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c
+++ b/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c
@@ -118,24 +118,24 @@ static void kprobe_multi_link_api_subtest(void)
})

GET_ADDR("bpf_fentry_test1", addrs[0]);
- GET_ADDR("bpf_fentry_test2", addrs[1]);
- GET_ADDR("bpf_fentry_test3", addrs[2]);
- GET_ADDR("bpf_fentry_test4", addrs[3]);
- GET_ADDR("bpf_fentry_test5", addrs[4]);
- GET_ADDR("bpf_fentry_test6", addrs[5]);
- GET_ADDR("bpf_fentry_test7", addrs[6]);
+ GET_ADDR("bpf_fentry_test3", addrs[1]);
+ GET_ADDR("bpf_fentry_test4", addrs[2]);
+ GET_ADDR("bpf_fentry_test5", addrs[3]);
+ GET_ADDR("bpf_fentry_test6", addrs[4]);
+ GET_ADDR("bpf_fentry_test7", addrs[5]);
+ GET_ADDR("bpf_fentry_test2", addrs[6]);
GET_ADDR("bpf_fentry_test8", addrs[7]);

#undef GET_ADDR

- cookies[0] = 1;
- cookies[1] = 2;
- cookies[2] = 3;
- cookies[3] = 4;
- cookies[4] = 5;
- cookies[5] = 6;
- cookies[6] = 7;
- cookies[7] = 8;
+ cookies[0] = 1; /* bpf_fentry_test1 */
+ cookies[1] = 2; /* bpf_fentry_test3 */
+ cookies[2] = 3; /* bpf_fentry_test4 */
+ cookies[3] = 4; /* bpf_fentry_test5 */
+ cookies[4] = 5; /* bpf_fentry_test6 */
+ cookies[5] = 6; /* bpf_fentry_test7 */
+ cookies[6] = 7; /* bpf_fentry_test2 */
+ cookies[7] = 8; /* bpf_fentry_test8 */

opts.kprobe_multi.addrs = (const unsigned long *) &addrs;
opts.kprobe_multi.cnt = ARRAY_SIZE(addrs);
@@ -146,14 +146,14 @@ static void kprobe_multi_link_api_subtest(void)
if (!ASSERT_GE(link1_fd, 0, "link1_fd"))
goto cleanup;

- cookies[0] = 8;
- cookies[1] = 7;
- cookies[2] = 6;
- cookies[3] = 5;
- cookies[4] = 4;
- cookies[5] = 3;
- cookies[6] = 2;
- cookies[7] = 1;
+ cookies[0] = 8; /* bpf_fentry_test1 */
+ cookies[1] = 7; /* bpf_fentry_test3 */
+ cookies[2] = 6; /* bpf_fentry_test4 */
+ cookies[3] = 5; /* bpf_fentry_test5 */
+ cookies[4] = 4; /* bpf_fentry_test6 */
+ cookies[5] = 3; /* bpf_fentry_test7 */
+ cookies[6] = 2; /* bpf_fentry_test2 */
+ cookies[7] = 1; /* bpf_fentry_test8 */

opts.kprobe_multi.flags = BPF_F_KPROBE_MULTI_RETURN;
prog_fd = bpf_program__fd(skel->progs.test_kretprobe);
@@ -178,12 +178,12 @@ static void kprobe_multi_attach_api_subtest(void)
struct kprobe_multi *skel = NULL;
const char *syms[8] = {
"bpf_fentry_test1",
- "bpf_fentry_test2",
"bpf_fentry_test3",
"bpf_fentry_test4",
"bpf_fentry_test5",
"bpf_fentry_test6",
"bpf_fentry_test7",
+ "bpf_fentry_test2",
"bpf_fentry_test8",
};
__u64 cookies[8];
@@ -195,14 +195,14 @@ static void kprobe_multi_attach_api_subtest(void)
skel->bss->pid = getpid();
skel->bss->test_cookie = true;

- cookies[0] = 1;
- cookies[1] = 2;
- cookies[2] = 3;
- cookies[3] = 4;
- cookies[4] = 5;
- cookies[5] = 6;
- cookies[6] = 7;
- cookies[7] = 8;
+ cookies[0] = 1; /* bpf_fentry_test1 */
+ cookies[1] = 2; /* bpf_fentry_test3 */
+ cookies[2] = 3; /* bpf_fentry_test4 */
+ cookies[3] = 4; /* bpf_fentry_test5 */
+ cookies[4] = 5; /* bpf_fentry_test6 */
+ cookies[5] = 6; /* bpf_fentry_test7 */
+ cookies[6] = 7; /* bpf_fentry_test2 */
+ cookies[7] = 8; /* bpf_fentry_test8 */

opts.syms = syms;
opts.cnt = ARRAY_SIZE(syms);
@@ -213,14 +213,14 @@ static void kprobe_multi_attach_api_subtest(void)
if (!ASSERT_OK_PTR(link1, "bpf_program__attach_kprobe_multi_opts"))
goto cleanup;

- cookies[0] = 8;
- cookies[1] = 7;
- cookies[2] = 6;
- cookies[3] = 5;
- cookies[4] = 4;
- cookies[5] = 3;
- cookies[6] = 2;
- cookies[7] = 1;
+ cookies[0] = 8; /* bpf_fentry_test1 */
+ cookies[1] = 7; /* bpf_fentry_test3 */
+ cookies[2] = 6; /* bpf_fentry_test4 */
+ cookies[3] = 5; /* bpf_fentry_test5 */
+ cookies[4] = 4; /* bpf_fentry_test6 */
+ cookies[5] = 3; /* bpf_fentry_test7 */
+ cookies[6] = 2; /* bpf_fentry_test2 */
+ cookies[7] = 1; /* bpf_fentry_test8 */

opts.retprobe = true;

diff --git a/tools/testing/selftests/bpf/progs/kprobe_multi.c b/tools/testing/selftests/bpf/progs/kprobe_multi.c
index 600be50800f8..8e06c49aa65a 100644
--- a/tools/testing/selftests/bpf/progs/kprobe_multi.c
+++ b/tools/testing/selftests/bpf/progs/kprobe_multi.c
@@ -54,21 +54,21 @@ static void kprobe_multi_check(void *ctx, bool is_return)

if (is_return) {
SET(kretprobe_test1_result, &bpf_fentry_test1, 8);
- SET(kretprobe_test2_result, &bpf_fentry_test2, 7);
- SET(kretprobe_test3_result, &bpf_fentry_test3, 6);
- SET(kretprobe_test4_result, &bpf_fentry_test4, 5);
- SET(kretprobe_test5_result, &bpf_fentry_test5, 4);
- SET(kretprobe_test6_result, &bpf_fentry_test6, 3);
- SET(kretprobe_test7_result, &bpf_fentry_test7, 2);
+ SET(kretprobe_test2_result, &bpf_fentry_test2, 2);
+ SET(kretprobe_test3_result, &bpf_fentry_test3, 7);
+ SET(kretprobe_test4_result, &bpf_fentry_test4, 6);
+ SET(kretprobe_test5_result, &bpf_fentry_test5, 5);
+ SET(kretprobe_test6_result, &bpf_fentry_test6, 4);
+ SET(kretprobe_test7_result, &bpf_fentry_test7, 3);
SET(kretprobe_test8_result, &bpf_fentry_test8, 1);
} else {
SET(kprobe_test1_result, &bpf_fentry_test1, 1);
- SET(kprobe_test2_result, &bpf_fentry_test2, 2);
- SET(kprobe_test3_result, &bpf_fentry_test3, 3);
- SET(kprobe_test4_result, &bpf_fentry_test4, 4);
- SET(kprobe_test5_result, &bpf_fentry_test5, 5);
- SET(kprobe_test6_result, &bpf_fentry_test6, 6);
- SET(kprobe_test7_result, &bpf_fentry_test7, 7);
+ SET(kprobe_test2_result, &bpf_fentry_test2, 7);
+ SET(kprobe_test3_result, &bpf_fentry_test3, 2);
+ SET(kprobe_test4_result, &bpf_fentry_test4, 3);
+ SET(kprobe_test5_result, &bpf_fentry_test5, 4);
+ SET(kprobe_test6_result, &bpf_fentry_test6, 5);
+ SET(kprobe_test7_result, &bpf_fentry_test7, 6);
SET(kprobe_test8_result, &bpf_fentry_test8, 8);
}

--
2.35.1