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);
