From mboxrd@z Thu Jan  1 00:00:00 1970
From: Oleg Nesterov <oleg@redhat.com>
Subject: Re: [PATCH v11 08/12] signal, x86: add SIGSYS info and make it
	synchronous.
Date: Mon, 27 Feb 2012 18:22:08 +0100
Message-ID: <20120227172208.GC10608@redhat.com>
References: <1330140111-17201-1-git-send-email-wad@chromium.org> <1330140111-17201-8-git-send-email-wad@chromium.org>
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To: Will Drewry <wad@chromium.org>
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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.