io_uring: synchronise IOPOLL on task_submit fail
io_req_task_submit() might be called for IOPOLL, do the fail path under
uring_lock to comply with IOPOLL synchronisation based solely on it.
Cc: stable@vger.kernel.org # 5.5+
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 ca46f31..5be33fd 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2126,15 +2126,16 @@ static void io_req_task_cancel(struct callback_head *cb)
static void __io_req_task_submit(struct io_kiocb *req)
{
struct io_ring_ctx *ctx = req->ctx;
+ bool fail;
- if (!__io_sq_thread_acquire_mm(ctx) &&
- !__io_sq_thread_acquire_files(ctx)) {
- mutex_lock(&ctx->uring_lock);
+ fail = __io_sq_thread_acquire_mm(ctx) ||
+ __io_sq_thread_acquire_files(ctx);
+ mutex_lock(&ctx->uring_lock);
+ if (!fail)
__io_queue_sqe(req, NULL);
- mutex_unlock(&ctx->uring_lock);
- } else {
+ else
__io_req_task_cancel(req, -EFAULT);
- }
+ mutex_unlock(&ctx->uring_lock);
}
static void io_req_task_submit(struct callback_head *cb)