[PATCH 5.10 105/157] io_uring: dont attempt IO reissue from the ring exit path

Greg Kroah-Hartman
2021-03-22T12:50:05Z

From: Jens Axboe <axboe@kernel.dk>

[ 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@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
fs/io_uring.c | 7 +++++++
1 file changed, 7 insertions(+)

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);

--
2.30.1