From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55249) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZOlRT-0003R4-H6 for qemu-devel@nongnu.org; Mon, 10 Aug 2015 07:40:36 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZOlRQ-0003R8-6x for qemu-devel@nongnu.org; Mon, 10 Aug 2015 07:40:35 -0400 Received: from mail-wi0-x233.google.com ([2a00:1450:400c:c05::233]:36702) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZOlRQ-0003Qk-0H for qemu-devel@nongnu.org; Mon, 10 Aug 2015 07:40:32 -0400 Received: by wicja10 with SMTP id ja10so33533318wic.1 for ; Mon, 10 Aug 2015 04:40:31 -0700 (PDT) Date: Mon, 10 Aug 2015 11:44:22 +0100 From: Stefan Hajnoczi Message-ID: <20150810104422.GF31433@stefanha-thinkpad.redhat.com> References: <20150729093135.GB22681@ubuntu-trusty> <20150730132744.GA11022@localhost.localdomain> <20150803004136.GC11733@ubuntu-trusty> <20150805185844.GD9878@localhost.localdomain> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="OzxllxdKGCiKxUZM" Content-Disposition: inline In-Reply-To: Subject: Re: [Qemu-devel] [sheepdog] [PATCH] sheepdog: fix overlapping metadata update List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Vasiliy Tolstov Cc: Kevin Wolf , Teruaki Ishizaki , Hitoshi Mitake , Hitoshi Mitake , Jeff Cody , qemu-devel@nongnu.org, sheepdog-ng@googlegroups.com, morita.kazutaka@gmail.com, Stefan Hajnoczi , Liu Yuan , sheepdog@lists.wpkg.org --OzxllxdKGCiKxUZM Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sun, Aug 09, 2015 at 05:03:14PM +0300, Vasiliy Tolstov wrote: > 2015-08-05 21:58 GMT+03:00 Jeff Cody : > > Hi Vasiliy, > > > > If you run configure with --disable-strip, it will not strip the > > debugging symbols from the binary after the build. Then, you can run > > gdb on qemu, and do a backtrace after you hit the segfault ('bt'). > > That may shed some light, and is a good place to start. >=20 >=20 > I'm try to debug (disable-strip), but i'm start vps from libvirt (i'm > add -s flag to qemu, to start gdb), but when i'm attach to remote > session,qemu aready dies, or all works fine. > does it possible to determine by this dmesg what happening in qemu > binary with debug symbols? > qemu-system-x86[34046]: segfault at 401364 ip 00007f33f52a1ff8 sp > 00007f3401ecad30 error 4 in qemu-system-x86_64[7f33f4efd000+518000] -s launches QEMU's gdbstub for *guest* debugging. It allows you to see the CPU and memory state inside the guest. It won't help you debug this segfault. Since the problem you encountered is a *QEMU* segfault, you need to use *host* GDB on the QEMU process instead. I'm not sure if libvirt sets the RLIMIT_CORE rlimit for the QEMU process (which could disable coredumps), but if your host uses systemd you may be able to inspect the coredump with gdb using coredumpctl(1). --OzxllxdKGCiKxUZM Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQEcBAEBAgAGBQJVyICGAAoJEJykq7OBq3PIXzIH/3++QMXrzD2F/f1Wk/4SDAbd nKBNKavShnoB8MK6uU14nPjS6nTxNJjCFlNo11QocK5PAnEAbsL3RqolnnEmXeZ7 lBD0zcX5B+LKr8mHFDBRzH/U27B6MeeXm3a8kdQjNu+BlvQ9x4f8sQ/DXHRSHWoM ayDZHKUWNjUEFf0S2K+xMXlJ+RuiZkppt3ViSlX/Met3EwO/Qayf0uFe7MBjwAnF reG9up81LZTi+tIOoJGsZjXAmcx44tODXx1TSILHzFrofFwSfMVC7sGoMfar3Zut QuI3lddg9FE2kp0w4or1/oPRHiHfHoIdWAtsfxYzGFXa0pMKTxUnLi5ZTdie8ZY= =f71p -----END PGP SIGNATURE----- --OzxllxdKGCiKxUZM--