io_uring: don't leak creds on SQO attach error

Attaching to already dead/dying SQPOLL task is disallowed in
io_sq_offload_create(), but cleanup is hand coded by calling
io_put_sq_data()/etc., that miss to put ctx->sq_creds.

Defer everything to error-path io_sq_thread_finish(), adding
ctx->sqd_list in the error case as well as finish will handle it.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index 6750739..ea2d3e1 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -7910,22 +7910,17 @@ static int io_sq_offload_create(struct io_ring_ctx *ctx,
 
                ret = 0;
                io_sq_thread_park(sqd);
+               list_add(&ctx->sqd_list, &sqd->ctx_list);
+               io_sqd_update_thread_idle(sqd);
                /* don't attach to a dying SQPOLL thread, would be racy */
-               if (attached && !sqd->thread) {
+               if (attached && !sqd->thread)
                        ret = -ENXIO;
-               } else {
-                       list_add(&ctx->sqd_list, &sqd->ctx_list);
-                       io_sqd_update_thread_idle(sqd);
-               }
                io_sq_thread_unpark(sqd);
 
-               if (ret < 0) {
-                       io_put_sq_data(sqd);
-                       ctx->sq_data = NULL;
-                       return ret;
-               } else if (attached) {
+               if (ret < 0)
+                       goto err;
+               if (attached)
                        return 0;
-               }
 
                if (p->flags & IORING_SETUP_SQ_AFF) {
                        int cpu = p->sq_thread_cpu;