From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752513Ab1JYGB6 (ORCPT ); Tue, 25 Oct 2011 02:01:58 -0400 Received: from e1.ny.us.ibm.com ([32.97.182.141]:44244 "EHLO e1.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751980Ab1JYGB5 (ORCPT ); Tue, 25 Oct 2011 02:01:57 -0400 Date: Tue, 25 Oct 2011 11:31:00 +0530 From: Ananth N Mavinakayanahalli To: Oleg Nesterov Cc: Srikar Dronamraju , Peter Zijlstra , Ingo Molnar , Steven Rostedt , Linux-mm , Arnaldo Carvalho de Melo , Linus Torvalds , Jonathan Corbet , Masami Hiramatsu , Hugh Dickins , Christoph Hellwig , Thomas Gleixner , Andi Kleen , Andrew Morton , Jim Keniston , Roland McGrath , LKML Subject: Re: [PATCH 13/X] uprobes: introduce UTASK_SSTEP_TRAPPED logic Message-ID: <20111025060059.GA8247@in.ibm.com> Reply-To: ananth@in.ibm.com References: <20110920115938.25326.93059.sendpatchset@srdronam.in.ibm.com> <20111015190007.GA30243@redhat.com> <20111019215139.GA16395@redhat.com> <20111019215344.GG16395@redhat.com> <20111022072030.GB24475@in.ibm.com> <20111024144127.GA14975@redhat.com> <20111024151614.GA6034@in.ibm.com> <20111024161306.GB19659@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20111024161306.GB19659@redhat.com> User-Agent: Mutt/1.5.17 (2007-11-01) x-cbid: 11102506-6078-0000-0000-00000213AF8D Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 24, 2011 at 06:13:06PM +0200, Oleg Nesterov wrote: > On 10/24, Ananth N Mavinakayanahalli wrote: > > > > Thinking further on this, in the normal 'running gdb on a core' case, we > > won't have this problem, as the binary that we point gdb to, will be a > > pristine one, without the uprobe int3s, right? > > Not sure I understand. > > I meant, if we have a binary with uprobes (iow, register_uprobe() installed > uprobes into that file), then gdb will see int3's with or without the core. > Or you can add uprobe into glibc, say you can probe getpid(). Now (again, > with or without the core) disassemble shows that getpid() starts with int3. > > But I guess you meant something else... No, you are right... my inference was wrong. On a core with a uprobe with an explicit raise(SIGABRT) does show the breakpoint. (gdb) disassemble start_thread2 Dump of assembler code for function start_thread2: 0x0000000000400831 <+0>: int3 0x0000000000400832 <+1>: mov %rsp,%rbp 0x0000000000400835 <+4>: sub $0x10,%rsp 0x0000000000400839 <+8>: mov %rdi,-0x8(%rbp) 0x000000000040083d <+12>: callq 0x400650 Now, I guess we need to agree on what is the acceptable behavior in the uprobes case. What's your suggestion? Ananth From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with ESMTP id 084A06B002D for ; Tue, 25 Oct 2011 02:03:19 -0400 (EDT) Received: from /spool/local by e2.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Tue, 25 Oct 2011 02:03:08 -0400 Received: from d03av03.boulder.ibm.com (d03av03.boulder.ibm.com [9.17.195.169]) by d01relay04.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p9P61Q9C225214 for ; Tue, 25 Oct 2011 02:01:26 -0400 Received: from d03av03.boulder.ibm.com (loopback [127.0.0.1]) by d03av03.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p9P61Lsx020156 for ; Tue, 25 Oct 2011 00:01:22 -0600 Date: Tue, 25 Oct 2011 11:31:00 +0530 From: Ananth N Mavinakayanahalli Subject: Re: [PATCH 13/X] uprobes: introduce UTASK_SSTEP_TRAPPED logic Message-ID: <20111025060059.GA8247@in.ibm.com> Reply-To: ananth@in.ibm.com References: <20110920115938.25326.93059.sendpatchset@srdronam.in.ibm.com> <20111015190007.GA30243@redhat.com> <20111019215139.GA16395@redhat.com> <20111019215344.GG16395@redhat.com> <20111022072030.GB24475@in.ibm.com> <20111024144127.GA14975@redhat.com> <20111024151614.GA6034@in.ibm.com> <20111024161306.GB19659@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20111024161306.GB19659@redhat.com> Sender: owner-linux-mm@kvack.org List-ID: To: Oleg Nesterov Cc: Srikar Dronamraju , Peter Zijlstra , Ingo Molnar , Steven Rostedt , Linux-mm , Arnaldo Carvalho de Melo , Linus Torvalds , Jonathan Corbet , Masami Hiramatsu , Hugh Dickins , Christoph Hellwig , Thomas Gleixner , Andi Kleen , Andrew Morton , Jim Keniston , Roland McGrath , LKML On Mon, Oct 24, 2011 at 06:13:06PM +0200, Oleg Nesterov wrote: > On 10/24, Ananth N Mavinakayanahalli wrote: > > > > Thinking further on this, in the normal 'running gdb on a core' case, we > > won't have this problem, as the binary that we point gdb to, will be a > > pristine one, without the uprobe int3s, right? > > Not sure I understand. > > I meant, if we have a binary with uprobes (iow, register_uprobe() installed > uprobes into that file), then gdb will see int3's with or without the core. > Or you can add uprobe into glibc, say you can probe getpid(). Now (again, > with or without the core) disassemble shows that getpid() starts with int3. > > But I guess you meant something else... No, you are right... my inference was wrong. On a core with a uprobe with an explicit raise(SIGABRT) does show the breakpoint. (gdb) disassemble start_thread2 Dump of assembler code for function start_thread2: 0x0000000000400831 <+0>: int3 0x0000000000400832 <+1>: mov %rsp,%rbp 0x0000000000400835 <+4>: sub $0x10,%rsp 0x0000000000400839 <+8>: mov %rdi,-0x8(%rbp) 0x000000000040083d <+12>: callq 0x400650 Now, I guess we need to agree on what is the acceptable behavior in the uprobes case. What's your suggestion? Ananth -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org