Re: [PATCH 5.14] io_uring: use right task for exiting checks

[Jens Axboe <axboe@kernel.dk>]

On Fri, Jul 9, 2021 at 7:46 PM Pavel Begunkov <asml.silence@gmail.com> wrote:
>
> When we use delayed_work for fallback execution of requests, current
> will be not of the submitter task, and so checks in io_req_task_submit()
> may not behave as expected. Currently, it leaves inline completions not
> flushed, so making io_ring_exit_work() to hang. Use the submitter task
> for all those checks.
>
> Cc: stable@vger.kernel.org
> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
> ---
>  fs/io_uring.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/io_uring.c b/fs/io_uring.c
> index 7167c61c6d1b..770fdcd7d3e4 100644
> --- a/fs/io_uring.c
> +++ b/fs/io_uring.c
> @@ -2016,7 +2016,7 @@ static void io_req_task_submit(struct io_kiocb *req)
>
>         /* ctx stays valid until unlock, even if we drop all ours ctx->refs */
>         mutex_lock(&ctx->uring_lock);
> -       if (!(current->flags & PF_EXITING) && !current->in_execve)
> +       if (!(req->task->flags & PF_EXITING) && !req->task->in_execve)
>                 __io_queue_sqe(req);
>         else
>                 io_req_complete_failed(req, -EFAULT);

I don't think that ->in_execve check is useful anymore now that we don't
have weak references to the files table, so it should probably just go
away.

-- 
Jens Axboe