| Message ID | 20241203202228.1274403-1-visitorckw@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | tracing: Fix cmp_entries_dup() to respect sort() comparison rules | expand |
diff --git a/kernel/trace/tracing_map.c b/kernel/trace/tracing_map.c index 3a56e7c8aa4f..1921ade45be3 100644 --- a/kernel/trace/tracing_map.c +++ b/kernel/trace/tracing_map.c @@ -845,15 +845,11 @@ int tracing_map_init(struct tracing_map *map) static int cmp_entries_dup(const void *A, const void *B) { const struct tracing_map_sort_entry *a, *b; - int ret = 0; a = *(const struct tracing_map_sort_entry **)A; b = *(const struct tracing_map_sort_entry **)B; - if (memcmp(a->key, b->key, a->elt->map->key_size)) - ret = 1; - - return ret; + return memcmp(a->key, b->key, a->elt->map->key_size); } static int cmp_entries_sum(const void *A, const void *B)
The cmp_entries_dup() function used as the comparator for sort() violated the symmetry and transitivity properties required by the sorting algorithm. Specifically, it returned 1 whenever memcmp() was non-zero, which broke the following expectations: * Symmetry: If x < y, then y > x. * Transitivity: If x < y and y < z, then x < z. These violations could lead to incorrect sorting and failure to correctly identify duplicate elements. Fix the issue by directly returning the result of memcmp(), which adheres to the required comparison properties. Fixes: 08d43a5fa063 ("tracing: Add lock-free tracing_map") Cc: stable@vger.kernel.org Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com> --- kernel/trace/tracing_map.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-)