Re: [PATCH v2] x86: signal: move save_altstack_ex out of generic headers

[Oleg Nesterov]

On 04/03, Nick Desaulniers wrote:
>
> --- a/arch/x86/kernel/signal.c
> +++ b/arch/x86/kernel/signal.c
> @@ -416,6 +416,7 @@ static int __setup_rt_frame(int sig, struct ksignal *ksig,
>  	return 0;
>  Efault:
>  	user_access_end();
> +	reset_altstack();
>  	return -EFAULT;
>  }
>  #else /* !CONFIG_X86_32 */
> @@ -507,6 +508,7 @@ static int __setup_rt_frame(int sig, struct ksignal *ksig,
>  
>  Efault:
>  	user_access_end();
> +	reset_altstack();
>  	return -EFAULT;
>  }

I must have missed something, but this looks just wrong.

reset_altstack() should be called when __setup_rt_frame() (and
unsafe_save_altstack() in particular) succeeds, not when it fails.

Nevermind, Al has already suggested to use signal_delivered()...

Oleg.