From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45222) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1addvQ-0001Cq-8M for qemu-devel@nongnu.org; Wed, 09 Mar 2016 08:13:17 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1addvM-0006qL-Ux for qemu-devel@nongnu.org; Wed, 09 Mar 2016 08:13:16 -0500 Received: from e06smtp15.uk.ibm.com ([195.75.94.111]:55755) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1addvM-0006qH-Lw for qemu-devel@nongnu.org; Wed, 09 Mar 2016 08:13:12 -0500 Received: from localhost by e06smtp15.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 9 Mar 2016 13:02:59 -0000 Received: from b06cxnps3075.portsmouth.uk.ibm.com (d06relay10.portsmouth.uk.ibm.com [9.149.109.195]) by d06dlp02.portsmouth.uk.ibm.com (Postfix) with ESMTP id C03762190056 for ; Wed, 9 Mar 2016 13:02:39 +0000 (GMT) Received: from d06av11.portsmouth.uk.ibm.com (d06av11.portsmouth.uk.ibm.com [9.149.37.252]) by b06cxnps3075.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id u29D2ugF61079666 for ; Wed, 9 Mar 2016 13:02:56 GMT Received: from d06av11.portsmouth.uk.ibm.com (localhost [127.0.0.1]) by d06av11.portsmouth.uk.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id u29D2ue5015894 for ; Wed, 9 Mar 2016 06:02:56 -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> From: Christian Borntraeger Message-ID: <56E01F00.7050905@de.ibm.com> Date: Wed, 9 Mar 2016 14:02:56 +0100 MIME-Version: 1.0 In-Reply-To: <56E01D3F.1060204@redhat.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 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.