This is a note to let you know that I've just added the patch titled io_uring: don't attempt IO reissue from the ring exit path to the 5.10-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: io_uring-don-t-attempt-io-reissue-from-the-ring-exit.patch and it can be found in the queue-5.10 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 420abb264b3a384425b20bcb00d97e82e89b60ab Author: Jens Axboe <axboe@xxxxxxxxx> Date: Tue Feb 23 19:17:35 2021 -0700 io_uring: don't attempt IO reissue from the ring exit path [ Upstream commit 7c977a58dc83366e488c217fd88b1469d242bee5 ] If we're exiting the ring, just let the IO fail with -EAGAIN as nobody will care anyway. It's not the right context to reissue from. Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/fs/io_uring.c b/fs/io_uring.c index 5746998799ab..7625b3e2db2c 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -2617,6 +2617,13 @@ static bool io_rw_reissue(struct io_kiocb *req, long res) return false; if ((res != -EAGAIN && res != -EOPNOTSUPP) || io_wq_current_is_worker()) return false; + /* + * If ref is dying, we might be running poll reap from the exit work. + * Don't attempt to reissue from that path, just let it fail with + * -EAGAIN. + */ + if (percpu_ref_is_dying(&req->ctx->refs)) + return false; ret = io_sq_thread_acquire_mm(req->ctx, req);