From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50740) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1erguq-0006Ci-Ki for qemu-devel@nongnu.org; Fri, 02 Mar 2018 04:23:49 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ergun-0003YY-C2 for qemu-devel@nongnu.org; Fri, 02 Mar 2018 04:23:48 -0500 Date: Fri, 2 Mar 2018 09:23:18 +0000 From: Stefan Hajnoczi Message-ID: <20180302092318.GA6026@stefanha-x1.localdomain> References: <079a5da7-6586-b974-6b99-e5de055b1bd1@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="+HP7ph2BbKc20aGI" Content-Disposition: inline In-Reply-To: <079a5da7-6586-b974-6b99-e5de055b1bd1@linux.vnet.ibm.com> Subject: Re: [Qemu-devel] [BUG] I/O thread segfault for QEMU on s390x List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Farhan Ali Cc: Christian Borntraeger , Cornelia Huck , Thomas Huth , Paolo Bonzini , mreitz@redhat.com, famz@redhat.com, QEMU Developers , "open list:virtio-ccw" --+HP7ph2BbKc20aGI Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Mar 01, 2018 at 09:33:35AM -0500, Farhan Ali wrote: > Hi, >=20 > I have been noticing some segfaults for QEMU on s390x, and I have been > hitting this issue quite reliably (at least once in 10 runs of a test cas= e). > The qemu version is 2.11.50, and I have systemd created coredumps > when this happens. >=20 > Here is a back trace of the segfaulting thread: The backtrace looks normal. Please post the QEMU command-line and the details of the segfault (which memory access faulted?). > #0 0x000003ffafed202c in swapcontext () from /lib64/libc.so.6 > #1 0x000002aa355c02ee in qemu_coroutine_new () at > util/coroutine-ucontext.c:164 > #2 0x000002aa355bec34 in qemu_coroutine_create > (entry=3Dentry@entry=3D0x2aa3550f7a8 , > opaque=3Dopaque@entry=3D0x3ffa002afa0) at util/qemu-coroutine.c:76 > #3 0x000002aa35510262 in blk_aio_prwv (blk=3D0x2aa65fbefa0, offset=3D out>, bytes=3D, qiov=3D0x3ffa002a9c0, > co_entry=3Dco_entry@entry=3D0x2aa3550f7a8 , flags=3D0, > cb=3D0x2aa35340a50 , opaque=3D0x3ffa002a960) = at > block/block-backend.c:1299 > #4 0x000002aa35510376 in blk_aio_preadv (blk=3D, > offset=3D, qiov=3D, flags=3D, > cb=3D, opaque=3D0x3ffa002a960) at block/block-backend.c:13= 92 > #5 0x000002aa3534114e in submit_requests (niov=3D, > num_reqs=3D, start=3D, mrb=3D, > blk=3D) at > /usr/src/debug/qemu-2.11.50/hw/block/virtio-blk.c:372 > #6 virtio_blk_submit_multireq (blk=3D, > mrb=3Dmrb@entry=3D0x3ffad77e640) at > /usr/src/debug/qemu-2.11.50/hw/block/virtio-blk.c:402 > #7 0x000002aa353422e0 in virtio_blk_handle_vq (s=3D0x2aa6611e7d8, > vq=3D0x3ffb0f5f010) at /usr/src/debug/qemu-2.11.50/hw/block/virtio-blk.c:= 620 > #8 0x000002aa3536655a in virtio_queue_notify_aio_vq > (vq=3Dvq@entry=3D0x3ffb0f5f010) at > /usr/src/debug/qemu-2.11.50/hw/virtio/virtio.c:1515 > #9 0x000002aa35366cd6 in virtio_queue_notify_aio_vq (vq=3D0x3ffb0f5f010)= at > /usr/src/debug/qemu-2.11.50/hw/virtio/virtio.c:1511 > #10 virtio_queue_host_notifier_aio_poll (opaque=3D0x3ffb0f5f078) at > /usr/src/debug/qemu-2.11.50/hw/virtio/virtio.c:2409 > #11 0x000002aa355a8ba4 in run_poll_handlers_once > (ctx=3Dctx@entry=3D0x2aa65f99310) at util/aio-posix.c:497 > #12 0x000002aa355a9b74 in run_poll_handlers (max_ns=3D, > ctx=3D0x2aa65f99310) at util/aio-posix.c:534 > #13 try_poll_mode (blocking=3Dtrue, ctx=3D0x2aa65f99310) at util/aio-posi= x.c:562 > #14 aio_poll (ctx=3D0x2aa65f99310, blocking=3Dblocking@entry=3Dtrue) at > util/aio-posix.c:602 > #15 0x000002aa353d2d0a in iothread_run (opaque=3D0x2aa65f990f0) at > iothread.c:60 > #16 0x000003ffb0f07e82 in start_thread () from /lib64/libpthread.so.0 > #17 0x000003ffaff91596 in thread_start () from /lib64/libc.so.6 >=20 >=20 > I don't have much knowledge about i/o threads and the block layer code in > QEMU, so I would like to report to the community about this issue. > I believe this very similar to the bug that I reported upstream couple of > days ago > (https://lists.gnu.org/archive/html/qemu-devel/2018-02/msg04452.html). >=20 > Any help would be greatly appreciated. >=20 > Thanks > Farhan >=20 --+HP7ph2BbKc20aGI Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEcBAEBAgAGBQJamRgGAAoJEJykq7OBq3PI/+EH/R/cAJDMD+oDd/B+tK9u3n3E KZdSeMO3/D9fkxZblUq+GpNix5+OtXZy1ca66GiiYq52yuJ+gf0pYgMyZGUq3DuZ Om2emUDq5W9+YpyLX9Cc7UxvOHxcDxWLv+nOm9gq+HWf+yEhoy7j0IxVh3bXmJf0 1lv3gAnYWbE/P0ANMJAY4LFdDU+ZaaONLKksOH+tXM+PsJgKolKi/7UJO/AWyiwx XHtlAQo7GJyznAoJtWBiKQ9tK10WrnFv6JchwtoVLliFyFKNOOZhvK2vTyC32lLB NL4XtmCjJ3d4yDI+GGI3RjRxh3pOroH7e5Y6Wc5WQLZxfZv3CnEUUysJ6cZmXvI= =phVF -----END PGP SIGNATURE----- --+HP7ph2BbKc20aGI--