Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751196Ab1BNRrv (ORCPT ); Mon, 14 Feb 2011 12:47:51 -0500 Received: from mx1.redhat.com ([209.132.183.28]:45416 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750739Ab1BNRrr (ORCPT ); Mon, 14 Feb 2011 12:47:47 -0500 Date: Mon, 14 Feb 2011 18:39:10 +0100 From: Oleg Nesterov To: Denys Vlasenko Cc: Tejun Heo , Roland McGrath , jan.kratochvil@redhat.com, linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org Subject: Re: [PATCH 1/1] ptrace: make sure do_wait() won't hang after PTRACE_ATTACH Message-ID: <20110214173910.GA15847@redhat.com> References: <20110204105343.GA12133@htj.dyndns.org> <20110207174821.GA1237@redhat.com> <20110209141803.GH3770@htj.dyndns.org> <201102132325.55353.vda.linux@googlemail.com> <20110214153149.GB8761@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1143 Lines: 29 On 02/14, Denys Vlasenko wrote: > > On Mon, Feb 14, 2011 at 4:31 PM, Oleg Nesterov wrote: > > On 02/13, Denys Vlasenko wrote: > >> > >> $ strace -tt sleep 30 > >> 23:02:15.619262 execve("/bin/sleep", ["sleep", "30"], [/* 30 vars */]) = 0 > >> ... > >> 23:02:15.622112 nanosleep({30, 0}, NULL) = ? ERESTART_RESTARTBLOCK (To be restarted) > >> 23:02:23.781165 --- SIGSTOP (Stopped (signal)) @ 0 (0) --- > >> 23:02:23.781251 --- SIGSTOP (Stopped (signal)) @ 0 (0) --- > >> ? ? (I forgot again why we see it twice. Another quirk I guess...) > > > > ? ? ?(this is correct, the tracee reports the signal=SIGSTOP, then > > ? ? ? it reports it actually stopps with exit_code=SIGSTOP) > > Ah, I see. Is there any way debugger can distinguish between these two > different stops? IIRC, the (only?) way to distinguish is to check last_siginfo != NULL via ptrace(PTRACE_GETSIGINFO). Oleg. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/