linux-kernel - Re: [PATCH 31/41] um: Don't restore current->blocked on error

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Message-ID: <20110816173830.GF29190@redhat.com>
Date:	Tue, 16 Aug 2011 19:38:30 +0200
From:	Oleg Nesterov <oleg@...hat.com>
To:	Matt Fleming <matt@...sole-pimps.org>
Cc:	linux-kernel@...r.kernel.org, Richard Weinberger <richard@....at>
Subject: Re: [PATCH 31/41] um: Don't restore current->blocked on error

On 08/11, Matt Fleming wrote:
>
> If we fail to setup the signal stack frame then we don't need to
> restore current->blocked because it is not modified by
> setup_signal_stack_*.

Yes. And this is simply wrong if TIF_RESTORE_SIGMASK. We can block
SIGSEGV which we need to dequeue.

ACK

> Cc: Oleg Nesterov <oleg@...hat.com>
> Cc: Richard Weinberger <richard@....at>
> Signed-off-by: Matt Fleming <matt.fleming@...el.com>
> ---
>  arch/um/kernel/signal.c |    8 ++------
>  1 files changed, 2 insertions(+), 6 deletions(-)
> 
> diff --git a/arch/um/kernel/signal.c b/arch/um/kernel/signal.c
> index 1812524..d177685 100644
> --- a/arch/um/kernel/signal.c
> +++ b/arch/um/kernel/signal.c
> @@ -66,13 +66,9 @@ static int handle_signal(struct pt_regs *regs, unsigned long signr,
>  #endif
>  		err = setup_signal_stack_si(sp, signr, ka, regs, info, oldset);
>  
> -	if (err) {
> -		spin_lock_irq(&current->sighand->siglock);
> -		current->blocked = *oldset;
> -		recalc_sigpending();
> -		spin_unlock_irq(&current->sighand->siglock);
> +	if (err)
>  		force_sigsegv(signr, current);
> -	} else {
> +	else {
>  		sigset_t blocked:
>  
>  		sigorsets(&blocked, &current->blocked, &ka->sa.sa_mask);
> -- 
> 1.7.4.4
> 

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