io_uring: check non-sync defer_list carefully

io_req_defer() do double-checked locking. Use proper helpers for that, i.e. list_empty_careful(). Signed-off-by: Pavel Begunkov <[email protected]> Signed-off-by: Jens Axboe <[email protected]>
josf · May 1, 2020 · 4ee3631 · 4ee3631
1 parent 7759a0b
commit 4ee3631
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/fs/io_uring.c b/fs/io_uring.c
@@ -5031,7 +5031,7 @@ static int io_req_defer(struct io_kiocb *req, const struct io_uring_sqe *sqe)
 	int ret;
 
 	/* Still need defer if there is pending req in defer list. */
-	if (!req_need_defer(req) && list_empty(&ctx->defer_list))
+	if (!req_need_defer(req) && list_empty_careful(&ctx->defer_list))
 		return 0;
 
 	if (!req->io && io_alloc_async_ctx(req))