Subject: Re: [PATCH v11 08/12] signal, x86: add SIGSYS info and make it synchronous.

From: Oleg Nesterov <[email-masked]>
Date: Mon, 27 Feb 2012 18:22:08 +0100

On 02/24, Will Drewry wrote:
>
> To ensure that SIGSYS delivery occurs on return from the triggering
> system call, SIGSYS is added to the SYNCHRONOUS_MASK macro.

Hmm. Can't understand... please help.

>  #define SYNCHRONOUS_MASK \
>  	(sigmask(SIGSEGV) | sigmask(SIGBUS) | sigmask(SIGILL) | \
> -	 sigmask(SIGTRAP) | sigmask(SIGFPE))
> +	 sigmask(SIGTRAP) | sigmask(SIGFPE) | sigmask(SIGSYS))

Why?

SYNCHRONOUS_MASK just tells dequeue_signal() "pick them first".
This is needed to make sure that the handler for, say SIGSEGV,
can use ucontext->ip as a faulting addr.

But seccomp adds info->si_call_addr, this looks unneeded.

Oleg.