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@xxxxxxxxxx>
-----
changelog:
v2->v3:
- Re-submitting the patch in plain text format as suggested by Michael
- Added the fixes tag
v1->v2:
- Addressed Jason's comment to remove the irq check and use
vhost_vdpa_unsetup_vq_irq() to avoid local variable vq
-----
diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
index 62a9bb0efc55..e00573b87aba 100644
--- a/drivers/vhost/vdpa.c
+++ b/drivers/vhost/vdpa.c
@@ -844,14 +844,10 @@ static int vhost_vdpa_open(struct inode *inode,
struct file *filep)
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)
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