Re: [PATCH] ptrace(2) single-stepping into signal handlers

cutaway
2005-06-05T13:44:46Z

----- Original Message -----
From: "Andi Kleen" <ak@suse.de>
To: "John Blackwood" <john.blackwood@ccur.com>
Cc: <linux-kernel@vger.kernel.org>; <roland@redhat.com>; <ak@suse.de>;
<akpm@osdl.org>; <bugsy@ccur.com>
Sent: Sunday, June 05, 2005 07:21
Subject: Re: [PATCH] ptrace(2) single-stepping into signal handlers

> On Fri, Jun 03, 2005 at 01:21:20PM -0400, John Blackwood wrote:
> > 1. Make the default behavior that we single-step to the next instruction
> > in the main (non-signal handler) stream of execution, instead of
> > single-stepping into the user's signal handler.
>
> I think it is better to not change the default behaviour. You risk
> breaking programs and there are much more that use ptrace than just gdb.

A performance trace profiler would want to step through signal handlers.
Sometimes they're an architected norm for a program rather than an abnormal
condition handler (ex. Lisp systems routinely handling GP faults on null
pointers rather than doing null pointer checks in critical loops)