This is a note to let you know that I've just added the patch titled
io_uring: fix link lookup racing with link timeout
to the 5.9-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-fix-link-lookup-racing-with-link-timeout.patch
and it can be found in the queue-5.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 9a472ef7a3690ac0b77ebfb04c88fa795de2adea Mon Sep 17 00:00:00 2001
From: Pavel Begunkov <asml.silence@xxxxxxxxx>
Date: Thu, 5 Nov 2020 22:31:37 +0000
Subject: io_uring: fix link lookup racing with link timeout
From: Pavel Begunkov <asml.silence@xxxxxxxxx>
commit 9a472ef7a3690ac0b77ebfb04c88fa795de2adea upstream.
We can't just go over linked requests because it may race with linked
timeouts. Take ctx->completion_lock in that case.
Cc: stable@xxxxxxxxxxxxxxx # v5.7+
Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/io_uring.c | 16 +++++++++++++++-
1 file changed, 15 insertions(+), 1 deletion(-)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -8176,7 +8176,21 @@ static bool io_timeout_remove_link(struc
static bool io_cancel_link_cb(struct io_wq_work *work, void *data)
{
- return io_match_link(container_of(work, struct io_kiocb, work), data);
+ struct io_kiocb *req = container_of(work, struct io_kiocb, work);
+ bool ret;
+
+ if (req->flags & REQ_F_LINK_TIMEOUT) {
+ unsigned long flags;
+ struct io_ring_ctx *ctx = req->ctx;
+
+ /* protect against races with linked timeouts */
+ spin_lock_irqsave(&ctx->completion_lock, flags);
+ ret = io_match_link(req, data);
+ spin_unlock_irqrestore(&ctx->completion_lock, flags);
+ } else {
+ ret = io_match_link(req, data);
+ }
+ return ret;
}
static void io_attempt_cancel(struct io_ring_ctx *ctx, struct io_kiocb *req)
Patches currently in stable-queue which might be from asml.silence@xxxxxxxxx are
queue-5.9/io_uring-don-t-miss-setting-io_wq_work_concurrent.patch
queue-5.9/io_uring-fix-link-lookup-racing-with-link-timeout.patch
