From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43259) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1addnx-0005rR-Qb for qemu-devel@nongnu.org; Wed, 09 Mar 2016 08:05:34 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1addns-0004lv-2Y for qemu-devel@nongnu.org; Wed, 09 Mar 2016 08:05:33 -0500 Received: from e06smtp14.uk.ibm.com ([195.75.94.110]:58146) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1addnr-0004lb-PQ for qemu-devel@nongnu.org; Wed, 09 Mar 2016 08:05:27 -0500 Received: from localhost by e06smtp14.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 9 Mar 2016 13:05:26 -0000 Received: from b06cxnps3074.portsmouth.uk.ibm.com (d06relay09.portsmouth.uk.ibm.com [9.149.109.194]) by d06dlp03.portsmouth.uk.ibm.com (Postfix) with ESMTP id 065881B0806B for ; Wed, 9 Mar 2016 13:05:49 +0000 (GMT) Received: from d06av03.portsmouth.uk.ibm.com (d06av03.portsmouth.uk.ibm.com [9.149.37.213]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u29D5Ni35374304 for ; Wed, 9 Mar 2016 13:05:23 GMT Received: from d06av03.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av03.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u29D5M1g006859 for ; Wed, 9 Mar 2016 06:05:22 -0700 References: <1455470231-5223-1-git-send-email-pbonzini@redhat.com> <1455470231-5223-6-git-send-email-pbonzini@redhat.com> <56E01544.6060305@de.ibm.com> <56E01D3F.1060204@redhat.com> <56E01F00.7050905@de.ibm.com> From: Christian Borntraeger Message-ID: <56E01F90.9020702@de.ibm.com> Date: Wed, 9 Mar 2016 14:05:20 +0100 MIME-Version: 1.0 In-Reply-To: <56E01F00.7050905@de.ibm.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 5/8] virtio-blk: fix "disabled data plane" mode List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini Cc: qemu-devel@nongnu.org On 03/09/2016 02:02 PM, Christian Borntraeger wrote: > On 03/09/2016 01:55 PM, Paolo Bonzini wrote: >> >> >> On 09/03/2016 13:21, Christian Borntraeger wrote: >>> I have some random crashes at startup >>> >>> Stack trace of thread 48326: >>> #0 0x000002aa2e0cce46 bdrv_co_do_rw (qemu-system-s390x) >>> #1 0x000002aa2e159e8e coroutine_trampoline (qemu-system-s390x) >>> #2 0x000003ffbc35150a __makecontext_ret (libc.so.6) >>> >>> >>> that I was able to bisect. >>> commit 2906cddfecff21af20eedab43288b485a679f9ac does crash regularly, >>> 2906cddfecff21af20eedab43288b485a679f9ac^ does not. >>> >>> I will try to find somebody that looks into that - unless you have an idea. >> >> The only random idea is to move >> >> vblk->dataplane_started = true >> >> to the beginning of virtio_blk_data_plane_start rather than the end. >> >> Paolo >> > > Indeed > > diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c > index 36f3d2b..1908d59 100644 > --- a/hw/block/dataplane/virtio-blk.c > +++ b/hw/block/dataplane/virtio-blk.c > @@ -195,6 +195,7 @@ void virtio_blk_data_plane_start(VirtIOBlockDataPlane *s) > if (vblk->dataplane_started || s->starting) { > return; > } > + vblk->dataplane_started = true; > > s->starting = true; > s->vq = virtio_get_queue(s->vdev, 0); > @@ -235,7 +236,6 @@ void virtio_blk_data_plane_start(VirtIOBlockDataPlane *s) > fail_guest_notifiers: > s->disabled = true; > s->starting = false; > - vblk->dataplane_started = true; > } > > /* Context: QEMU global mutex held */ > > seems to fix the issue. Hmmm, no another crash, just seems to happen less often.