From: Hui Zhu <[email protected]> When back-porting test_progs to different kernel versions, I encountered an issue where the test_cgroup_iter_memcg test would falsely pass even when bpf_mem_cgroup_page_state() failed.
The problem occurs when test_progs compiled on one kernel version is executed on another kernel with different enum values for memory statistics (e.g., NR_ANON_MAPPED, NR_FILE_PAGES). In such cases, bpf_mem_cgroup_page_state() returns -1 to indicate failure, but the test didn't check for this error condition and incorrectly reported success. This patch adds explicit checks to ensure bpf_mem_cgroup_page_state() doesn't return -1 before validating the actual statistics values. This prevents false positives when running test_progs in cross-kernel environments. Signed-off-by: Hui Zhu <[email protected]> --- .../selftests/bpf/prog_tests/cgroup_iter_memcg.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/tools/testing/selftests/bpf/prog_tests/cgroup_iter_memcg.c b/tools/testing/selftests/bpf/prog_tests/cgroup_iter_memcg.c index a5afd16705f0..13b299512429 100644 --- a/tools/testing/selftests/bpf/prog_tests/cgroup_iter_memcg.c +++ b/tools/testing/selftests/bpf/prog_tests/cgroup_iter_memcg.c @@ -53,6 +53,8 @@ static void test_anon(struct bpf_link *link, struct memcg_query *memcg_query) if (!ASSERT_OK(read_stats(link), "read stats")) goto cleanup; + ASSERT_NEQ(memcg_query->nr_anon_mapped, (unsigned long)-1, + "bpf_mem_cgroup_page_state NR_ANON_MAPPED"); ASSERT_GT(memcg_query->nr_anon_mapped, 0, "final anon mapped val"); cleanup: @@ -88,6 +90,10 @@ static void test_file(struct bpf_link *link, struct memcg_query *memcg_query) if (!ASSERT_OK(read_stats(link), "read stats")) goto cleanup_map; + ASSERT_NEQ(memcg_query->nr_file_pages, (unsigned long)-1, + "bpf_mem_cgroup_page_state NR_FILE_PAGES"); + ASSERT_NEQ(memcg_query->nr_file_mapped, (unsigned long)-1, + "bpf_mem_cgroup_page_state NR_FILE_MAPPED"); ASSERT_GT(memcg_query->nr_file_pages, 0, "final file value"); ASSERT_GT(memcg_query->nr_file_mapped, 0, "final file mapped value"); @@ -119,6 +125,8 @@ static void test_shmem(struct bpf_link *link, struct memcg_query *memcg_query) if (!ASSERT_OK(read_stats(link), "read stats")) goto cleanup; + ASSERT_NEQ(memcg_query->nr_shmem, (unsigned long)-1, + "bpf_mem_cgroup_page_state NR_SHMEM"); ASSERT_GT(memcg_query->nr_shmem, 0, "final shmem value"); cleanup: @@ -143,6 +151,8 @@ static void test_kmem(struct bpf_link *link, struct memcg_query *memcg_query) if (!ASSERT_OK(read_stats(link), "read stats")) goto cleanup; + ASSERT_NEQ(memcg_query->memcg_kmem, (unsigned long)-1, + "bpf_mem_cgroup_page_state MEMCG_KMEM"); ASSERT_GT(memcg_query->memcg_kmem, 0, "kmem value"); cleanup: @@ -170,6 +180,8 @@ static void test_pgfault(struct bpf_link *link, struct memcg_query *memcg_query) if (!ASSERT_OK(read_stats(link), "read stats")) goto cleanup; + ASSERT_NEQ(memcg_query->pgfault, (unsigned long)-1, + "bpf_mem_cgroup_page_state PGFAULT"); ASSERT_GT(memcg_query->pgfault, 0, "final pgfault val"); cleanup: -- 2.43.0
