We flush under vq mutex when changing backends. This creates a deadlock as workqueue being flushed needs this lock as well.
https://bugzilla.redhat.com/show_bug.cgi?id=612421 Drop the vq mutex before flush: we have the device mutex which is sufficient to prevent another ioctl from touching the vq. Signed-off-by: Michael S. Tsirkin <[email protected]> --- drivers/vhost/net.c | 5 +++++ 1 files changed, 5 insertions(+), 0 deletions(-) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index 28d7786..50df58e6 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -534,11 +534,16 @@ static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd) rcu_assign_pointer(vq->private_data, sock); vhost_net_enable_vq(n, vq); done: + mutex_unlock(&vq->mutex); + if (oldsock) { vhost_net_flush_vq(n, index); fput(oldsock->file); } + mutex_unlock(&n->dev.mutex); + return 0; + err_vq: mutex_unlock(&vq->mutex); err: -- 1.7.2.rc0.14.g41c1c _______________________________________________ Virtualization mailing list [email protected] https://lists.linux-foundation.org/mailman/listinfo/virtualization
