This is a note to let you know that I've just added the patch titled
io_uring: always lock in io_apoll_task_func
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-always-lock-in-io_apoll_task_func.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.
>From stable-owner@xxxxxxxxxxxxxxx Tue Sep 12 16:05:05 2023
From: Pavel Begunkov <asml.silence@xxxxxxxxx>
Date: Tue, 12 Sep 2023 15:02:48 +0100
Subject: io_uring: always lock in io_apoll_task_func
To: stable@xxxxxxxxxxxxxxx
Cc: Jens Axboe <axboe@xxxxxxxxx>, asml.silence@xxxxxxxxx, Dylan Yudaken <dylany@xxxxxxxx>
Message-ID: <9f8a30b981705fa8fef31ad76c9bf7192b8db2a4.1694524751.git.asml.silence@xxxxxxxxx>
From: Pavel Begunkov <asml.silence@xxxxxxxxx>
From: Dylan Yudaken <dylany@xxxxxxxx>
[ upstream commit c06c6c5d276707e04cedbcc55625e984922118aa ]
This is required for the failure case (io_req_complete_failed) and is
missing.
The alternative would be to only lock in the failure path, however all of
the non-error paths in io_poll_check_events that do not do not return
IOU_POLL_NO_ACTION end up locking anyway. The only extraneous lock would
be for the multishot poll overflowing the CQE ring, however multishot poll
would probably benefit from being locked as it will allow completions to
be batched.
So it seems reasonable to lock always.
Signed-off-by: Dylan Yudaken <dylany@xxxxxxxx>
Link: https://lore.kernel.org/r/20221124093559.3780686-3-dylany@xxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
io_uring/io_uring.c | 1 +
1 file changed, 1 insertion(+)
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -5571,6 +5571,7 @@ static void io_apoll_task_func(struct io
if (ret > 0)
return;
+ io_tw_lock(req->ctx, locked);
io_poll_remove_entries(req);
spin_lock(&ctx->completion_lock);
hash_del(&req->hash_node);
Patches currently in stable-queue which might be from stable-owner@xxxxxxxxxxxxxxx are
queue-5.10/io_uring-always-lock-in-io_apoll_task_func.patch
queue-5.10/io_uring-break-out-of-iowq-iopoll-on-teardown.patch
queue-5.10/io_uring-break-iopolling-on-signal.patch
