From 0187c7989a5cedd4f88bba76839cc9c44fb3fc81 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Tue, 2 Sep 2014 16:12:41 +0300 Subject: [PATCH] virtio-net: don't run bh on vm stopped commit 783e7706937fe15523b609b545587a028a2bdd03 virtio-net: stop/start bh when appropriate is incomplete: BH might execute within the same main loop iteration but after vmstop, so in theory, we might trigger an assertion. I was unable to reproduce this in practice, but it seems clear enough that the potential is there, so worth fixing. Cc: qemu-stable@nongnu.org Reported-by: Stefan Hajnoczi Signed-off-by: Michael S. Tsirkin --- hw/net/virtio-net.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c index 268eff9df8..365e266b74 100644 --- a/hw/net/virtio-net.c +++ b/hw/net/virtio-net.c @@ -1224,7 +1224,12 @@ static void virtio_net_tx_timer(void *opaque) VirtIONetQueue *q = opaque; VirtIONet *n = q->n; VirtIODevice *vdev = VIRTIO_DEVICE(n); - assert(vdev->vm_running); + /* This happens when device was stopped but BH wasn't. */ + if (!vdev->vm_running) { + /* Make sure tx waiting is set, so we'll run when restarted. */ + assert(q->tx_waiting); + return; + } q->tx_waiting = 0; @@ -1244,7 +1249,12 @@ static void virtio_net_tx_bh(void *opaque) VirtIODevice *vdev = VIRTIO_DEVICE(n); int32_t ret; - assert(vdev->vm_running); + /* This happens when device was stopped but BH wasn't. */ + if (!vdev->vm_running) { + /* Make sure tx waiting is set, so we'll run when restarted. */ + assert(q->tx_waiting); + return; + } q->tx_waiting = 0;