linux-kernel - Re: [PATCH] aio: Fix incorrect usage of eventfd_signal

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Message-ID: <87ee9rcokg.ffs@tglx>
Date:   Tue, 14 Sep 2021 14:46:23 +0200
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Xie Yongji <xieyongji@...edance.com>, bcrl@...ck.org,
        viro@...iv.linux.org.uk, axboe@...nel.dk
Cc:     linux-aio@...ck.org, linux-fsdevel@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] aio: Fix incorrect usage of eventfd_signal_allowed()

On Mon, Sep 13 2021 at 19:19, Xie Yongji wrote:
> We should defer eventfd_signal() to the workqueue when
> eventfd_signal_allowed() return false rather than return
> true.
>
> Fixes: b542e383d8c0 ("eventfd: Make signal recursion protection a task bit")
> Signed-off-by: Xie Yongji <xieyongji@...edance.com>
> ---
>  fs/aio.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/aio.c b/fs/aio.c
> index 51b08ab01dff..8822e3ed4566 100644
> --- a/fs/aio.c
> +++ b/fs/aio.c
> @@ -1695,7 +1695,7 @@ static int aio_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
>  		list_del(&iocb->ki_list);
>  		iocb->ki_res.res = mangle_poll(mask);
>  		req->done = true;
> -		if (iocb->ki_eventfd && eventfd_signal_allowed()) {
> +		if (iocb->ki_eventfd && !eventfd_signal_allowed()) {

Thanks for catching that!

>  			iocb = NULL;
>  			INIT_WORK(&req->work, aio_poll_put_work);
>  			schedule_work(&req->work);