bpf: Call the missed btf_record_free() when map creation fails

When security_bpf_map_create() in map_create() fails, map_create() will
call btf_put() and ->map_free() callback to free the map. It doesn't
free the btf_record of map value, so add the missed btf_record_free()
when map creation fails.

However btf_record_free() needs to be called after ->map_free() just
like bpf_map_free_deferred() did, because ->map_free() may use the
btf_record to free the special fields in preallocated map value. So
factor out bpf_map_free() helper to free the map, btf_record, and btf
orderly and use the helper in both map_create() and
bpf_map_free_deferred().

Signed-off-by: Hou Tao <houtao1@huawei.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20240912012845.3458483-2-houtao@huaweicloud.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 593822d3d393fdda1f9d0c724e5b97ba881b21a4..8a4117f6d76107df037a5ee80b78a3d3fd810d38 100644 (file)
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -735,15 +735,11 @@ void bpf_obj_free_fields(const struct btf_record *rec, void *obj)
        }
 }
 
-/* called from workqueue */
-static void bpf_map_free_deferred(struct work_struct *work)
+static void bpf_map_free(struct bpf_map *map)
 {
-       struct bpf_map *map = container_of(work, struct bpf_map, work);
        struct btf_record *rec = map->record;
        struct btf *btf = map->btf;
 
-       security_bpf_map_free(map);
-       bpf_map_release_memcg(map);
        /* implementation dependent freeing */
        map->ops->map_free(map);
        /* Delay freeing of btf_record for maps, as map_free
@@ -762,6 +758,16 @@ static void bpf_map_free_deferred(struct work_struct *work)
        btf_put(btf);
 }
 
+/* called from workqueue */
+static void bpf_map_free_deferred(struct work_struct *work)
+{
+       struct bpf_map *map = container_of(work, struct bpf_map, work);
+
+       security_bpf_map_free(map);
+       bpf_map_release_memcg(map);
+       bpf_map_free(map);
+}
+
 static void bpf_map_put_uref(struct bpf_map *map)
 {
        if (atomic64_dec_and_test(&map->usercnt)) {
@@ -1413,8 +1419,7 @@ static int map_create(union bpf_attr *attr)
 free_map_sec:
        security_bpf_map_free(map);
 free_map:
-       btf_put(map->btf);
-       map->ops->map_free(map);
+       bpf_map_free(map);
 put_token:
        bpf_token_put(token);
        return err;