From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754460Ab1GVNjN (ORCPT ); Fri, 22 Jul 2011 09:39:13 -0400 Received: from mail-fx0-f52.google.com ([209.85.161.52]:44920 "EHLO mail-fx0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754349Ab1GVNjL (ORCPT ); Fri, 22 Jul 2011 09:39:11 -0400 Date: Fri, 22 Jul 2011 15:39:07 +0200 From: Tejun Heo To: Denys Vlasenko Cc: Oleg Nesterov , Jan Kratochvil , lkml Subject: Re: Merging ptrace branch into mainline Message-ID: <20110722133907.GL2622@htj.dyndns.org> References: <20110722103059.GK2622@htj.dyndns.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 22, 2011 at 01:40:36PM +0200, Denys Vlasenko wrote: > On Fri, Jul 22, 2011 at 12:30 PM, Tejun Heo wrote: > To what cases of ptrace stops is this applicable? > > I thought with PTRACE_O_TRACESYSGOOD the problem with SIGTRAP > being special under strace is dealt with: now both user-sent > SIGTRAPs and ones generated by int3 instruction are handled correctly > in current strace git. > > Is it about single-stepping? Strace doesn't use PTRACE_SIGLESTEP, > and I didn't have the need yet to familiarize myself with it. > Does it generate SIGTRAP? Single step and breakpoints use SIGTRAP and there are some variances on the information being reported depending on archs and IIRC it isn't always possible to discern those debug traps from kill(SIGTRAP)'s from userland. I think cleaning up what information is reported via siginfo on debug traps should resolve this too. Thansk. -- tejun