diff --git a/tools/testing/selftests/bpf/prog_tests/htab_update.c b/tools/testing/selftests/bpf/prog_tests/htab_update.c index d0b405eb2..bd29a915b 100644 --- a/tools/testing/selftests/bpf/prog_tests/htab_update.c +++ b/tools/testing/selftests/bpf/prog_tests/htab_update.c
[ ... ]
+static void test_lru_hash_map_update_elem(enum bpf_map_type map_type) +{
- int err, map_fd, i, key, nr_cpus, max_entries = 128;
- u64 *values, value = 0xDEADC0DE;
- nr_cpus = libbpf_num_possible_cpus();
- if (!ASSERT_GT(nr_cpus, 0, "libbpf_num_possible_cpus"))
return;- values = calloc(nr_cpus, sizeof(u64));
[ ... ]
- err = bpf_map_lookup_elem(map_fd, &key, values);
- if (!ASSERT_OK(err, "bpf_map_lookup_elem"))
goto out;- if (!ASSERT_EQ(*values, 0, "bpf_map_lookup_elem value"))
goto out;- for (key = 1; key < max_entries; key++) {
err = bpf_map_lookup_elem(map_fd, &key, values);if (!ASSERT_OK(err, "bpf_map_lookup_elem"))goto out;if (!ASSERT_EQ(*values, value, "bpf_map_lookup_elem value"))goto out;- }
When test_lru_hash_map_update_elem() is called with BPF_MAP_TYPE_LRU_PERCPU_HASH via test_update_lru_percpu_hash_map(), should all CPU values be checked rather than just *values?
For percpu maps, bpf_map_lookup_elem() returns an array with one value per CPU. The test allocates space for nr_cpus values but only verifies the first element. This means values for CPUs 1 through nr_cpus-1 are not validated.
Looking at tools/testing/selftests/bpf/prog_tests/lookup_and_delete.c, the pattern for percpu maps is to loop through all CPUs:
for (i = 0; i < nr_cpus; i++) { val = value[i]; /* check val */ }
For BPF_MAP_TYPE_LRU_HASH this is correct, but for BPF_MAP_TYPE_LRU_PERCPU_HASH the test may pass even if non-primary CPUs have incorrect values.
+out:
- close(map_fd);
- free(values);
+}
+static void test_update_lru_hash_map(void) +{
- test_lru_hash_map_update_elem(BPF_MAP_TYPE_LRU_HASH);
+}
+static void test_update_lru_percpu_hash_map(void) +{
- test_lru_hash_map_update_elem(BPF_MAP_TYPE_LRU_PERCPU_HASH);
+}
[ ... ]
--- AI reviewed your patch. Please fix the bug or email reply why it's not a bug. See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md
CI run summary: https://github.com/kernel-patches/bpf/actions/runs/19864460617