On 2/28/26 1:25 AM, Hui Zhu wrote:
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.
This patch adds explicit checks to ensure bpf_mem_cgroup_page_state()
doesn't return -1 before validating the actual statistics values.
Signed-off-by: Hui Zhu <[email protected]>
---
.../selftests/bpf/prog_tests/cgroup_iter_memcg.c | 10 ++++++++++
1 file changed, 10 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 88fc3e83d2b7..9eadfbd3fdb9 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:
@@ -144,6 +152,8 @@ 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_vm_events PGFAULT");
ASSERT_GT(memcg_query->pgfault, 0, "final pgfault val");
cleanup:
Emil mentioned in the v3 thread that we don't need these checks [0]. I
agree. Now that you're using the bpf co-re enum helpers, the stat
indexes won't become an issue in a cross-kernel secenario. This patch
can be dropped.
[0]
https://lore.kernel.org/bpf/[email protected]/T/#m7cb6edf90ed4daaeda38b746363317405f198f20
