From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 8957 invoked by alias); 12 May 2009 16:06:18 -0000 Received: (qmail 8946 invoked by uid 22791); 12 May 2009 16:06:17 -0000 X-SWARE-Spam-Status: No, hits=-2.5 required=5.0 tests=AWL,BAYES_00,SPF_HELO_PASS,SPF_PASS X-Spam-Check-By: sourceware.org Received: from mx2.redhat.com (HELO mx2.redhat.com) (66.187.237.31) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Tue, 12 May 2009 16:06:10 +0000 Received: from int-mx2.corp.redhat.com (int-mx2.corp.redhat.com [172.16.27.26]) by mx2.redhat.com (8.13.8/8.13.8) with ESMTP id n4CG685t024114; Tue, 12 May 2009 12:06:08 -0400 Received: from ns3.rdu.redhat.com (ns3.rdu.redhat.com [10.11.255.199]) by int-mx2.corp.redhat.com (8.13.1/8.13.1) with ESMTP id n4CG67XW020226; Tue, 12 May 2009 12:06:08 -0400 Received: from localhost.localdomain (dst61.hsv.redhat.com [172.16.16.175]) by ns3.rdu.redhat.com (8.13.8/8.13.8) with ESMTP id n4CG63eA006147; Tue, 12 May 2009 12:06:06 -0400 Message-ID: <4A099E6B.8090501@redhat.com> Date: Tue, 12 May 2009 16:06:00 -0000 From: David Smith User-Agent: Thunderbird 2.0.0.21 (X11/20090320) MIME-Version: 1.0 To: Roland McGrath CC: Maynard Johnson , systemtap@sourceware.org, "Frank Ch. Eigler" Subject: Re: Backward compatibility for insn probe point References: <49D3E3DF.1000108@us.ibm.com> <49F61D09.8090503@redhat.com> <49F8C1C0.8070208@us.ibm.com> <49F9E71D.2070500@redhat.com> <20090430203302.5FFA0FC3BF@magilla.sf.frob.com> In-Reply-To: <20090430203302.5FFA0FC3BF@magilla.sf.frob.com> Content-Type: text/plain; charset=ISO-8859-1 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/msg00563.txt.bz2 Roland McGrath wrote: >> Off the top of my head that might mean there is a specific ppc64 utrace >> problem. >> >> Roland, do you know of any problems with original utrace doing >> UTRACE_ACTION_SINGLESTEP on ppc64? > > Sorry, I can't remember anything in particular. There might well have been > some issue that I've forgotten. I've done some more debugging here, and I thought I'd let you know what I've found. The problem occurs on all versions of 2.6.25 I've found (which uses the original utrace). On the earliest version of 2.6.26 I've found (2.6.26.3-17.fc9.ppc64) which uses the new utrace, this works correctly. Digging a bit deeper into the behavior on failing kernels, I've found that if you set up an insn probe point and a syscall probe, you get only one insn probe hit before each syscall. Note that gdb is fully able to do instruction stepping on failing kernels, so ptrace seems to be working correctly. -- David Smith dsmith@redhat.com Red Hat http://www.redhat.com 256.217.0141 (direct) 256.837.0057 (fax)