From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59936) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1elhaZ-0006Lm-Ti for qemu-devel@nongnu.org; Tue, 13 Feb 2018 15:54:09 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1elhaW-0002n8-Sx for qemu-devel@nongnu.org; Tue, 13 Feb 2018 15:54:07 -0500 Received: from mx01.kamp.de ([82.141.2.16]:38929) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1elhaW-0002kd-I2 for qemu-devel@nongnu.org; Tue, 13 Feb 2018 15:54:04 -0500 Received: from submission.kamp.de ([195.62.97.28]) by kerio.kamp.de with ESMTPS (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256 bits)) for qemu-devel@nongnu.org; Tue, 13 Feb 2018 21:53:57 +0100 References: <1513866427-27125-1-git-send-email-mst@redhat.com> <1513866427-27125-11-git-send-email-mst@redhat.com> From: Peter Lieven Message-ID: <800aef3f-56c1-b896-1c93-24e2a523833d@kamp.de> Date: Tue, 13 Feb 2018 21:53:58 +0100 MIME-Version: 1.0 In-Reply-To: <1513866427-27125-11-git-send-email-mst@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Content-Language: en-US Subject: Re: [Qemu-devel] [Qemu-stable] [PULL 10/25] virtio_error: don't invoke status callbacks List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" , qemu-devel@nongnu.org Cc: Ilya Maximets , Peter Maydell , qemu-stable@nongnu.org Am 21.12.2017 um 15:29 schrieb Michael S. Tsirkin: > Backends don't need to know what frontend requested a reset, > and notifying then from virtio_error is messy because > virtio_error itself might be invoked from backend. > > Let's just set the status directly. > > Cc: qemu-stable@nongnu.org > Reported-by: Ilya Maximets > Signed-off-by: Michael S. Tsirkin > --- > hw/virtio/virtio.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c > index ad564b0..d6002ee 100644 > --- a/hw/virtio/virtio.c > +++ b/hw/virtio/virtio.c > @@ -2469,7 +2469,7 @@ void GCC_FMT_ATTR(2, 3) virtio_error(VirtIODevice *vdev, const char *fmt, ...) > va_end(ap); > > if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) { > - virtio_set_status(vdev, vdev->status | VIRTIO_CONFIG_S_NEEDS_RESET); > + vdev->status = vdev->status | VIRTIO_CONFIG_S_NEEDS_RESET; > virtio_notify_config(vdev); > } > Is it possible that this patch introduces a stall in I/O and a deadlock on a drain all? I have seen Qemu VMs being I/O stalled and deadlocking on a vm stop command in blk_drain_all. This happened after a longer storage outage. I am asking just theoretically because I have seen this behaviour first when we backported this patch in our stable 2.9 branch. Thank you, Peter