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. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=211711 Signed-off-by: Gautam Dawar <[email protected]> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c index 62a9bb0efc55..d1c3a33c6239 100644 --- a/drivers/vhost/vdpa.c +++ b/drivers/vhost/vdpa.c @@ -849,7 +849,7 @@ static void vhost_vdpa_clean_irq(struct vhost_vdpa *v) for (i = 0; i < v->nvqs; i++) { vq = &v->vqs[i]; - if (vq->call_ctx.producer.irq) + if (vq->call_ctx.producer.irq >= 0) irq_bypass_unregister_producer(&vq->call_ctx.producer); } }
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