Re: [PATCH v3] vhost_vdpa: fix the missing irq_bypass_unregister_producer() invocation
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: 2021-02-23 12:50:13
On Tue, Feb 23, 2021 at 06:15:07PM +0530, 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.
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 <redacted>A bit better but still: Applying: vhost_vdpa: fix the missing irq_bypass_unregister_producer() invocation error: corrupt patch at line 6 error: could not build fake ancestor Patch failed at 0001 vhost_vdpa: fix the missing irq_bypass_unregister_producer() invocation hint: Use 'git am --show-current-patch=diff' to see the failed patch you also want to include acks you got on the previous versions.
quoted hunk ↗ jump to hunk
----- 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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