From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 10052 invoked by alias); 28 Apr 2009 18:02:57 -0000 Received: (qmail 9848 invoked by uid 22791); 28 Apr 2009 18:02:56 -0000 X-SWARE-Spam-Status: No, hits=-2.0 required=5.0 tests=AWL,BAYES_00 X-Spam-Check-By: sourceware.org Received: from e28smtp09.in.ibm.com (HELO e28smtp09.in.ibm.com) (59.145.155.9) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Tue, 28 Apr 2009 18:02:49 +0000 Received: from d28relay02.in.ibm.com (d28relay02.in.ibm.com [9.184.220.59]) by e28smtp09.in.ibm.com (8.13.1/8.13.1) with ESMTP id n3SHRnl0010202 for ; Tue, 28 Apr 2009 22:57:49 +0530 Received: from d28av01.in.ibm.com (d28av01.in.ibm.com [9.184.220.63]) by d28relay02.in.ibm.com (8.13.8/8.13.8/NCO v9.2) with ESMTP id n3SI2hid1474796 for ; Tue, 28 Apr 2009 23:32:43 +0530 Received: from d28av01.in.ibm.com (loopback [127.0.0.1]) by d28av01.in.ibm.com (8.13.1/8.13.3) with ESMTP id n3SI2hi9007744 for ; Tue, 28 Apr 2009 23:32:43 +0530 Received: from [9.124.216.114] ([9.124.216.114]) by d28av01.in.ibm.com (8.13.1/8.12.11) with ESMTP id n3SI2gXq007729; Tue, 28 Apr 2009 23:32:43 +0530 Message-ID: <49F74546.8040206@linux.vnet.ibm.com> Date: Tue, 28 Apr 2009 18:02:00 -0000 From: Prerna Saxena User-Agent: Thunderbird 2.0.0.19 (X11/20090105) MIME-Version: 1.0 To: Mark Wielaard CC: systemtap@sourceware.org, roland@redhat.com Subject: [Query] Re: dwarf unwinder (only works on i386/x86_64) References: <1239977157.2336.33.camel@fedora.wildebeest.org> In-Reply-To: <1239977157.2336.33.camel@fedora.wildebeest.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-IsSubscribed: yes Mailing-List: contact systemtap-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: systemtap-owner@sourceware.org X-SW-Source: 2009-q2/txt/msg00460.txt.bz2 Hi Mark, An elementary query regarding the dwarf-unwinder implementation... Mark Wielaard wrote: > ...... > > I am working on using the dwarf unwinder also for user space > backtracing. First using the debug_frame tables that we also are using > for the kernel case, but maybe switching to the eh_frame tables (it > isn't clear which one is really the most accurate at the moment, we > might need to consult both, but I am trying to avoid doing that for > now). > > I was trying to contrast the ".eh_frame" vs ".debug_frame" specifications for keeping track of stack backtraces. Both appear rather similar wrt information they maintain. The Exception header ".eh_frame" section seems to be present in vmlinux even when kernel is compiled without debuginfo. i. what gcc flags cause this section to be compiled ? ii. This section seemingly appears to be a better bet than DWARF to base the unwinder on--- because a ".debug_frame" based unwinder might not be useful in case of a kernel complied without debuginfo. Looks like I'm missing some reasoning here, could you throw some light ? :-) > Cheers, > > Mark > > Regards, -- Prerna Saxena Linux Technology Centre, IBM Systems and Technology Lab, Bangalore, India