Re: [PATCH v2] vhost vdpa: fix the missing irq_bypass_unregister_producer() invocation
From: Jason Wang <hidden>
Date: 2021-02-23 10:13:26
On 2021/2/23 6:00 下午, Gautam Dawar wrote:
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 <https://bugzilla.kernel.org/show_bug.cgi?id=211711> Signed-off-by: Gautam Dawar <gdawar@xilinx.com <mailto:gdawar@xilinx.com>> ----- changelog: v1->v2: - Addressed Jason's comment to remove the irq check and use vhost_vdpa_unsetup_vq_irq() to avoid local variable vq -----
Acked-by: Jason Wang <redacted>
quoted hunk ↗ jump to hunk
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)