This is a note to let you know that I've just added the patch titled
io-wq: remove spurious bit clear on task_work addition
to the 5.15-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-wq-remove-spurious-bit-clear-on-task_work-addition.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From e47498afeca9a0c6d07eeeacc46d563555a3f677 Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@xxxxxxxxx>
Date: Mon, 6 Dec 2021 10:49:04 -0700
Subject: io-wq: remove spurious bit clear on task_work addition
From: Jens Axboe <axboe@xxxxxxxxx>
commit e47498afeca9a0c6d07eeeacc46d563555a3f677 upstream.
There's a small race here where the task_work could finish and drop
the worker itself, so that by the time that task_work_add() returns
with a successful addition we've already put the worker.
The worker callbacks clear this bit themselves, so we don't actually
need to manually clear it in the caller. Get rid of it.
Reported-by: syzbot+b60c982cb0efc5e05a47@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/io-wq.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -359,10 +359,8 @@ static bool io_queue_worker_create(struc
init_task_work(&worker->create_work, func);
worker->create_index = acct->index;
- if (!task_work_add(wq->task, &worker->create_work, TWA_SIGNAL)) {
- clear_bit_unlock(0, &worker->create_state);
+ if (!task_work_add(wq->task, &worker->create_work, TWA_SIGNAL))
return true;
- }
clear_bit_unlock(0, &worker->create_state);
fail_release:
io_worker_release(worker);
Patches currently in stable-queue which might be from axboe@xxxxxxxxx are
queue-5.15/iocost-fix-divide-by-zero-on-donation-from-low-hweight-cgroup.patch
queue-5.15/io-wq-check-for-wq-exit-after-adding-new-worker-task_work.patch
queue-5.15/io-wq-remove-spurious-bit-clear-on-task_work-addition.patch
