Re: [PATCH] uprobes: Remove redundant spinlock in uprobe_deny_signal

[Oleg Nesterov]

On 07/31, Liao Chang wrote:
>
> --- a/kernel/events/uprobes.c
> +++ b/kernel/events/uprobes.c
> @@ -1979,9 +1979,7 @@ bool uprobe_deny_signal(void)
>       WARN_ON_ONCE(utask->state != UTASK_SSTEP);
>  
>       if (task_sigpending(t)) {
> -             spin_lock_irq(&t->sighand->siglock);
>               clear_tsk_thread_flag(t, TIF_SIGPENDING);
> -             spin_unlock_irq(&t->sighand->siglock);

Agreed, in this case ->siglock buys nothing, another signal can come
right after spin_unlock().

Acked-by: Oleg Nesterov <o...@redhat.com>