From: Gautam Dawar gdawar.xilinx@gmail.com
commit 4c050286bb202cffd5467c1cba982dff391d62e1 upstream.
When qemu with vhost-vdpa netdevice is run for the first time, it works well. But after the VM is powered off, the next qemu run causes kernel panic due to a NULL pointer dereference in irq_bypass_register_producer().
When the VM is powered off, vhost_vdpa_clean_irq() misses on calling irq_bypass_unregister_producer() for irq 0 because of the existing check.
This leaves stale producer nodes, which are reset in vhost_vring_call_reset() when vhost_dev_init() is invoked during the second qemu run.
As the node member of struct irq_bypass_producer is also initialized to zero, traversal on the producers list causes crash due to NULL pointer dereference.
Fixes: 2cf1ba9a4d15c ("vhost_vdpa: implement IRQ offloading in vhost_vdpa") Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=211711 Signed-off-by: Gautam Dawar gdawar.xilinx@gmail.com Acked-by: Jason Wang jasowang@redhat.com Link: https://lore.kernel.org/r/20210224114845.104173-1-gdawar.xilinx@gmail.com Signed-off-by: Michael S. Tsirkin mst@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/vhost/vdpa.c | 8 ++------ 1 file changed, 2 insertions(+), 6 deletions(-)
--- a/drivers/vhost/vdpa.c +++ b/drivers/vhost/vdpa.c @@ -910,14 +910,10 @@ err:
static void vhost_vdpa_clean_irq(struct vhost_vdpa *v) { - struct vhost_virtqueue *vq; int i;
- for (i = 0; i < v->nvqs; i++) { - vq = &v->vqs[i]; - if (vq->call_ctx.producer.irq) - irq_bypass_unregister_producer(&vq->call_ctx.producer); - } + for (i = 0; i < v->nvqs; i++) + vhost_vdpa_unsetup_vq_irq(v, i); }
static int vhost_vdpa_release(struct inode *inode, struct file *filep)