* [PATCH v3] vhost_vdpa: fix the missing irq_bypass_unregister_producer() invocation
@ 2021-02-23 12:45 Gautam Dawar
2021-02-23 12:49 ` Michael S. Tsirkin
0 siblings, 1 reply; 3+ messages in thread
From: Gautam Dawar @ 2021-02-23 12:45 UTC (permalink / raw)
To: virtualization, Jason Wang, mst, martinh, gdawar, hanand
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.com>
-----
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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^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH v3] vhost_vdpa: fix the missing irq_bypass_unregister_producer() invocation
2021-02-23 12:45 [PATCH v3] vhost_vdpa: fix the missing irq_bypass_unregister_producer() invocation Gautam Dawar
@ 2021-02-23 12:49 ` Michael S. Tsirkin
2021-02-24 11:51 ` Gautam Dawar
0 siblings, 1 reply; 3+ messages in thread
From: Michael S. Tsirkin @ 2021-02-23 12:49 UTC (permalink / raw)
To: Gautam Dawar; +Cc: martinh, hanand, gdawar, virtualization
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 <gdawar@xilinx.com>
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.
> -----
> 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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^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH v3] vhost_vdpa: fix the missing irq_bypass_unregister_producer() invocation
2021-02-23 12:49 ` Michael S. Tsirkin
@ 2021-02-24 11:51 ` Gautam Dawar
0 siblings, 0 replies; 3+ messages in thread
From: Gautam Dawar @ 2021-02-24 11:51 UTC (permalink / raw)
To: Michael S. Tsirkin; +Cc: martinh, hanand, gdawar, virtualization
Hi Michael,
I've submitted a fresh patch including the ack from Jason and after
testing with git am.
Regards,
Gautam
On Tue, 23 Feb 2021 at 18:20, Michael S. Tsirkin <mst@redhat.com> wrote:
>
> 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 <gdawar@xilinx.com>
>
>
> 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.
>
> > -----
> > 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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2021-02-23 12:45 [PATCH v3] vhost_vdpa: fix the missing irq_bypass_unregister_producer() invocation Gautam Dawar
2021-02-23 12:49 ` Michael S. Tsirkin
2021-02-24 11:51 ` Gautam Dawar
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