5.4-stable review patch. If anyone has any objections, please let me know.
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From: Kuan-Wei Chiu visitorckw@gmail.com
commit e63fbd5f6810ed756bbb8a1549c7d4132968baa9 upstream.
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.
Cc: stable@vger.kernel.org Fixes: 08d43a5fa063 ("tracing: Add lock-free tracing_map") Link: https://lore.kernel.org/20241203202228.1274403-1-visitorckw@gmail.com Signed-off-by: Kuan-Wei Chiu visitorckw@gmail.com Signed-off-by: Steven Rostedt (Google) rostedt@goodmis.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/trace/tracing_map.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-)
--- a/kernel/trace/tracing_map.c +++ b/kernel/trace/tracing_map.c @@ -845,15 +845,11 @@ int tracing_map_init(struct tracing_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)