From mboxrd@z Thu Jan 1 00:00:00 1970 From: Frederik Thuysbaert Subject: Re: [Xen-devel] Xen blktap driver for Ceph RBD : Anybody wants to test ? :p Date: Fri, 16 Aug 2013 10:27:02 +0200 Message-ID: <520DE256.80400@gmail.com> References: <6035A0D088A63A46850C3988ED045A4B62E86BF8@BITCOM1.int.sbss.com.au> <6035A0D088A63A46850C3988ED045A4B62F433FE@BITCOM1.int.sbss.com.au> <6035A0D088A63A46850C3988ED045A4B62F43442@BITCOM1.int.sbss.com.au> <6035A0D088A63A46850C3988ED045A4B63891798@BITCOM1.int.sbss.com.au> <6035A0D088A63A46850C3988ED045A4B6389552A@BITCOM1.int.sbss.com.au> <520A4945.1030907@gmail.com> <520B4339.6090209@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-wg0-f43.google.com ([74.125.82.43]:39682 "EHLO mail-wg0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751149Ab3HPI1F (ORCPT ); Fri, 16 Aug 2013 04:27:05 -0400 Received: by mail-wg0-f43.google.com with SMTP id z12so1291577wgg.34 for ; Fri, 16 Aug 2013 01:27:04 -0700 (PDT) In-Reply-To: Sender: ceph-devel-owner@vger.kernel.org List-ID: To: Sylvain Munaut Cc: James Harper , =?ISO-8859-1?Q?Pasi_K?= =?ISO-8859-1?Q?=E4rkk=E4inen?= , "ceph-devel@vger.kernel.org" , "xen-devel@lists.xen.org" Hi Sylvain, >> I'm not quite sure what u mean, can u give some more information on how I do >> this? I compiled tapdisk with ./configure CFLAGS=-g, but I'm not sure this >> is what u meant. > > Yes, ./configure CFLAGS=-g LDFLAGS=-g is a good start. > >... > > Then once you have a core file, you can use gdb along with the tapdisk > executable to generate a meaningful backtrace of where the crash > I did 2 runs, with a cold reboot in between just to be sure. I don't think I'm getting a lot of valuable information, but I will post it anyway. The reason for the cold reboot was a 'Cannot access memory at address ...' in gdb after the first frame, I thought it could help. Here's what I got: try 1: Core was generated by `tapdisk'. Program terminated with signal 11, Segmentation fault. #0 0x00007fb42d2082d7 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/x86_64-linux-gnu/libpthread.so.0 (gdb) bt #0 0x00007fb42d2082d7 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/x86_64-linux-gnu/libpthread.so.0 Cannot access memory at address 0x7fb42f081c38 (gdb) frame 0 #0 0x00007fb42d2082d7 in pthread_cond_wait@@GLIBC_2.3.2 () from /lib/x86_64-linux-gnu/libpthread.so.0 (gdb) list 77 } 78 79 int 80 main(int argc, char *argv[]) 81 { 82 char *control; 83 int c, err, nodaemon; 84 FILE *out; 85 86 control = NULL; (gdb) info locals No symbol table info available. try 2: Core was generated by `tapdisk'. Program terminated with signal 11, Segmentation fault. #0 0x00007fe05a721e6b in poll () from /lib/x86_64-linux-gnu/libc.so.6 (gdb) bt #0 0x00007fe05a721e6b in poll () from /lib/x86_64-linux-gnu/libc.so.6 Cannot access memory at address 0x7fe05c2ba518 (gdb) frame 0 #0 0x00007fe05a721e6b in poll () from /lib/x86_64-linux-gnu/libc.so.6 (gdb) list 77 } 78 79 int 80 main(int argc, char *argv[]) 81 { 82 char *control; 83 int c, err, nodaemon; 84 FILE *out; 85 86 control = NULL; (gdb) info locals No symbol table info available. Regards, - Frederik