On Wed, 02 Mar 2022, Michael S. Tsirkin wrote: > On Wed, Mar 02, 2022 at 07:54:21AM +0000, Lee Jones wrote: > > vhost_vsock_handle_tx_kick() already holds the mutex during its call > > to vhost_get_vq_desc(). All we have to do is take the same lock > > during virtqueue clean-up and we mitigate the reported issues. > > > > Link: https://syzkaller.appspot.com/bug?extid=279432d30d825e63ba00 > > > > Cc: <stable@xxxxxxxxxxxxxxx> > > Reported-by: syzbot+adc3cb32385586bec859@xxxxxxxxxxxxxxxxxxxxxxxxx > > Signed-off-by: Lee Jones <lee.jones@xxxxxxxxxx> > > --- > > drivers/vhost/vhost.c | 2 ++ > > 1 file changed, 2 insertions(+) > > > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > > index 59edb5a1ffe28..bbaff6a5e21b8 100644 > > --- a/drivers/vhost/vhost.c > > +++ b/drivers/vhost/vhost.c > > @@ -693,6 +693,7 @@ void vhost_dev_cleanup(struct vhost_dev *dev) > > int i; > > > > for (i = 0; i < dev->nvqs; ++i) { > > + mutex_lock(&dev->vqs[i]->mutex); > > if (dev->vqs[i]->error_ctx) > > eventfd_ctx_put(dev->vqs[i]->error_ctx); > > if (dev->vqs[i]->kick) > > @@ -700,6 +701,7 @@ void vhost_dev_cleanup(struct vhost_dev *dev) > > if (dev->vqs[i]->call_ctx.ctx) > > eventfd_ctx_put(dev->vqs[i]->call_ctx.ctx); > > vhost_vq_reset(dev, dev->vqs[i]); > > + mutex_unlock(&dev->vqs[i]->mutex); > > } > > So this is a mitigation plan but the bug is still there though > we don't know exactly what it is. I would prefer adding something like > WARN_ON(mutex_is_locked(vqs[i]->mutex) here - does this make sense? As a rework to this, or as a subsequent patch? Just before the first lock I assume? -- Lee Jones [李琼斯] Principal Technical Lead - Developer Services Linaro.org │ Open source software for Arm SoCs Follow Linaro: Facebook | Twitter | Blog
