6.12-stable review patch. If anyone has any objections, please let me know.
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From: Mykyta Yatsenko yatsenko@meta.com
[ Upstream commit 105eb5dc74109a9f53c2f26c9a918d9347a73595 ]
bpf_cookie can fail on perf_event_open(), when it runs after the task_work selftest. The task_work test causes perf to lower sysctl_perf_event_sample_rate, and bpf_cookie uses sample_freq, which is validated against that sysctl. As a result, perf_event_open() rejects the attr if the (now tighter) limit is exceeded.
From perf_event_open():
if (attr.freq) { if (attr.sample_freq > sysctl_perf_event_sample_rate) return -EINVAL; } else { if (attr.sample_period & (1ULL << 63)) return -EINVAL; }
Switch bpf_cookie to use sample_period, which is not checked against sysctl_perf_event_sample_rate.
Signed-off-by: Mykyta Yatsenko yatsenko@meta.com Signed-off-by: Andrii Nakryiko andrii@kernel.org Link: https://lore.kernel.org/bpf/20250925215230.265501-1-mykyta.yatsenko5@gmail.c... Signed-off-by: Sasha Levin sashal@kernel.org --- tools/testing/selftests/bpf/prog_tests/bpf_cookie.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c b/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c index 6befa870434bc..f97f560bafb20 100644 --- a/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c +++ b/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c @@ -450,8 +450,7 @@ static void pe_subtest(struct test_bpf_cookie *skel) attr.size = sizeof(attr); attr.type = PERF_TYPE_SOFTWARE; attr.config = PERF_COUNT_SW_CPU_CLOCK; - attr.freq = 1; - attr.sample_freq = 10000; + attr.sample_period = 100000; pfd = syscall(__NR_perf_event_open, &attr, -1, 0, -1, PERF_FLAG_FD_CLOEXEC); if (!ASSERT_GE(pfd, 0, "perf_fd")) goto cleanup;