io_uring: ensure task_work gets run as part of cancelations

commit 78a780602075d8b00c98070fa26e389b3b3efa72 upstream.

If we successfully cancel a work item but that work item needs to be
processed through task_work, then we can be sleeping uninterruptibly
in io_uring_cancel_generic() and never process it. Hence we don't
make forward progress and we end up with an uninterruptible sleep
warning.

While in there, correct a comment that should be IFF, not IIF.

Reported-and-tested-by: syzbot+21e6887c0be14181206d@syzkaller.appspotmail.com
Cc: stable@vger.kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Jens Axboe 2021-12-09 08:54:29 -07:00 committed by Greg Kroah-Hartman
parent eb313c47b2
commit 8e12976c0c

View File

@ -9775,7 +9775,7 @@ static void io_uring_drop_tctx_refs(struct task_struct *task)
/*
* Find any io_uring ctx that this task has registered or done IO on, and cancel
* requests. @sqd should be not-null IIF it's an SQPOLL thread cancellation.
* requests. @sqd should be not-null IFF it's an SQPOLL thread cancellation.
*/
static void io_uring_cancel_generic(bool cancel_all, struct io_sq_data *sqd)
{
@ -9816,8 +9816,10 @@ static void io_uring_cancel_generic(bool cancel_all, struct io_sq_data *sqd)
cancel_all);
}
prepare_to_wait(&tctx->wait, &wait, TASK_UNINTERRUPTIBLE);
prepare_to_wait(&tctx->wait, &wait, TASK_INTERRUPTIBLE);
io_run_task_work();
io_uring_drop_tctx_refs(current);
/*
* If we've seen completions, retry without waiting. This
* avoids a race where a completion comes in before we did