Re: [PATCH 1/4] io_uring: dont kill fasync under completion_lock

[Pavel Begunkov <asml.silence@xxxxxxxxx>]

On 02/01/2021 16:06, Pavel Begunkov wrote:
>       CPU0                    CPU1
>        ----                    ----
>   lock(&new->fa_lock);
>                                local_irq_disable();
>                                lock(&ctx->completion_lock);
>                                lock(&new->fa_lock);
>   <Interrupt>
>     lock(&ctx->completion_lock);
> 
>  *** DEADLOCK ***
> 
> Move kill_fasync() out of io_commit_cqring() to io_cqring_ev_posted(),
> so it doesn't hold completion_lock while doing it. That saves from the
> reported deadlock, and it's just nice to shorten the locking time and
> untangle nested locks (compl_lock -> wq_head::lock).

Need to resend this one

-- 
Pavel Begunkov