* [PATCH net 1/2] vhost: use mutex_lock_nested() in vhost_dev_lock_vqs()
@ 2018-01-23 9:27 Jason Wang
2018-01-23 9:27 ` [PATCH net 2/2] vhost: do not try to access device IOTLB when not initialized Jason Wang
` (2 more replies)
0 siblings, 3 replies; 7+ messages in thread
From: Jason Wang @ 2018-01-23 9:27 UTC (permalink / raw)
To: mst, jasowang, linux-kernel; +Cc: netdev, virtualization
We used to call mutex_lock() in vhost_dev_lock_vqs() which tries to
hold mutexes of all virtqueues. This may confuse lockdep to report a
possible deadlock because of trying to hold locks belong to same
class. Switch to use mutex_lock_nested() to avoid false positive.
Fixes: 6b1e6cc7855b0 ("vhost: new device IOTLB API")
Reported-by: syzbot+dbb7c1161485e61b0241@syzkaller.appspotmail.com
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
drivers/vhost/vhost.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 33ac2b1..549771a 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -904,7 +904,7 @@ static void vhost_dev_lock_vqs(struct vhost_dev *d)
{
int i = 0;
for (i = 0; i < d->nvqs; ++i)
- mutex_lock(&d->vqs[i]->mutex);
+ mutex_lock_nested(&d->vqs[i]->mutex, i);
}
static void vhost_dev_unlock_vqs(struct vhost_dev *d)
--
2.7.4
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH net 2/2] vhost: do not try to access device IOTLB when not initialized
2018-01-23 9:27 [PATCH net 1/2] vhost: use mutex_lock_nested() in vhost_dev_lock_vqs() Jason Wang
@ 2018-01-23 9:27 ` Jason Wang
2018-01-23 15:58 ` Michael S. Tsirkin
2018-01-23 15:57 ` [PATCH net 1/2] vhost: use mutex_lock_nested() in vhost_dev_lock_vqs() Michael S. Tsirkin
2018-01-24 21:38 ` David Miller
2 siblings, 1 reply; 7+ messages in thread
From: Jason Wang @ 2018-01-23 9:27 UTC (permalink / raw)
To: mst, jasowang, linux-kernel; +Cc: virtualization, netdev
The code will try to access dev->iotlb when processing
VHOST_IOTLB_INVALIDATE even if it was not initialized which may lead
to NULL pointer dereference. Fixes this by check dev->iotlb before.
Fixes: 6b1e6cc7855b0 ("vhost: new device IOTLB API")
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
drivers/vhost/vhost.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 549771a..5727b18 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1015,6 +1015,10 @@ static int vhost_process_iotlb_msg(struct vhost_dev *dev,
vhost_iotlb_notify_vq(dev, msg);
break;
case VHOST_IOTLB_INVALIDATE:
+ if (!dev->iotlb) {
+ ret = -EFAULT;
+ break;
+ }
vhost_vq_meta_reset(dev);
vhost_del_umem_range(dev->iotlb, msg->iova,
msg->iova + msg->size - 1);
--
2.7.4
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH net 1/2] vhost: use mutex_lock_nested() in vhost_dev_lock_vqs()
2018-01-23 9:27 [PATCH net 1/2] vhost: use mutex_lock_nested() in vhost_dev_lock_vqs() Jason Wang
2018-01-23 9:27 ` [PATCH net 2/2] vhost: do not try to access device IOTLB when not initialized Jason Wang
@ 2018-01-23 15:57 ` Michael S. Tsirkin
2018-01-24 21:38 ` David Miller
2 siblings, 0 replies; 7+ messages in thread
From: Michael S. Tsirkin @ 2018-01-23 15:57 UTC (permalink / raw)
To: Jason Wang; +Cc: netdev, linux-kernel, virtualization
On Tue, Jan 23, 2018 at 05:27:25PM +0800, Jason Wang wrote:
> We used to call mutex_lock() in vhost_dev_lock_vqs() which tries to
> hold mutexes of all virtqueues. This may confuse lockdep to report a
> possible deadlock because of trying to hold locks belong to same
> class. Switch to use mutex_lock_nested() to avoid false positive.
>
> Fixes: 6b1e6cc7855b0 ("vhost: new device IOTLB API")
> Reported-by: syzbot+dbb7c1161485e61b0241@syzkaller.appspotmail.com
> Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
> ---
> drivers/vhost/vhost.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index 33ac2b1..549771a 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -904,7 +904,7 @@ static void vhost_dev_lock_vqs(struct vhost_dev *d)
> {
> int i = 0;
> for (i = 0; i < d->nvqs; ++i)
> - mutex_lock(&d->vqs[i]->mutex);
> + mutex_lock_nested(&d->vqs[i]->mutex, i);
> }
>
> static void vhost_dev_unlock_vqs(struct vhost_dev *d)
> --
> 2.7.4
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH net 2/2] vhost: do not try to access device IOTLB when not initialized
2018-01-23 9:27 ` [PATCH net 2/2] vhost: do not try to access device IOTLB when not initialized Jason Wang
@ 2018-01-23 15:58 ` Michael S. Tsirkin
0 siblings, 0 replies; 7+ messages in thread
From: Michael S. Tsirkin @ 2018-01-23 15:58 UTC (permalink / raw)
To: Jason Wang; +Cc: netdev, linux-kernel, virtualization
On Tue, Jan 23, 2018 at 05:27:26PM +0800, Jason Wang wrote:
> The code will try to access dev->iotlb when processing
> VHOST_IOTLB_INVALIDATE even if it was not initialized which may lead
> to NULL pointer dereference. Fixes this by check dev->iotlb before.
>
> Fixes: 6b1e6cc7855b0 ("vhost: new device IOTLB API")
> Signed-off-by: Jason Wang <jasowang@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
> ---
> drivers/vhost/vhost.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index 549771a..5727b18 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -1015,6 +1015,10 @@ static int vhost_process_iotlb_msg(struct vhost_dev *dev,
> vhost_iotlb_notify_vq(dev, msg);
> break;
> case VHOST_IOTLB_INVALIDATE:
> + if (!dev->iotlb) {
> + ret = -EFAULT;
> + break;
> + }
> vhost_vq_meta_reset(dev);
> vhost_del_umem_range(dev->iotlb, msg->iova,
> msg->iova + msg->size - 1);
> --
> 2.7.4
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH net 1/2] vhost: use mutex_lock_nested() in vhost_dev_lock_vqs()
2018-01-23 9:27 [PATCH net 1/2] vhost: use mutex_lock_nested() in vhost_dev_lock_vqs() Jason Wang
2018-01-23 9:27 ` [PATCH net 2/2] vhost: do not try to access device IOTLB when not initialized Jason Wang
2018-01-23 15:57 ` [PATCH net 1/2] vhost: use mutex_lock_nested() in vhost_dev_lock_vqs() Michael S. Tsirkin
@ 2018-01-24 21:38 ` David Miller
2018-01-24 21:46 ` Michael S. Tsirkin
2 siblings, 1 reply; 7+ messages in thread
From: David Miller @ 2018-01-24 21:38 UTC (permalink / raw)
To: jasowang; +Cc: mst, linux-kernel, virtualization, netdev
From: Jason Wang <jasowang@redhat.com>
Date: Tue, 23 Jan 2018 17:27:25 +0800
> We used to call mutex_lock() in vhost_dev_lock_vqs() which tries to
> hold mutexes of all virtqueues. This may confuse lockdep to report a
> possible deadlock because of trying to hold locks belong to same
> class. Switch to use mutex_lock_nested() to avoid false positive.
>
> Fixes: 6b1e6cc7855b0 ("vhost: new device IOTLB API")
> Reported-by: syzbot+dbb7c1161485e61b0241@syzkaller.appspotmail.com
> Signed-off-by: Jason Wang <jasowang@redhat.com>
Michael, I see you ACK'd this, meaning that you're OK with these two
fixes going via my net tree?
Thanks.
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH net 1/2] vhost: use mutex_lock_nested() in vhost_dev_lock_vqs()
2018-01-24 21:38 ` David Miller
@ 2018-01-24 21:46 ` Michael S. Tsirkin
2018-01-24 21:55 ` David Miller
0 siblings, 1 reply; 7+ messages in thread
From: Michael S. Tsirkin @ 2018-01-24 21:46 UTC (permalink / raw)
To: David Miller; +Cc: jasowang, linux-kernel, virtualization, netdev
On Wed, Jan 24, 2018 at 04:38:30PM -0500, David Miller wrote:
> From: Jason Wang <jasowang@redhat.com>
> Date: Tue, 23 Jan 2018 17:27:25 +0800
>
> > We used to call mutex_lock() in vhost_dev_lock_vqs() which tries to
> > hold mutexes of all virtqueues. This may confuse lockdep to report a
> > possible deadlock because of trying to hold locks belong to same
> > class. Switch to use mutex_lock_nested() to avoid false positive.
> >
> > Fixes: 6b1e6cc7855b0 ("vhost: new device IOTLB API")
> > Reported-by: syzbot+dbb7c1161485e61b0241@syzkaller.appspotmail.com
> > Signed-off-by: Jason Wang <jasowang@redhat.com>
>
> Michael, I see you ACK'd this, meaning that you're OK with these two
> fixes going via my net tree?
>
> Thanks.
Yes - this seems to be what Jason wanted (judging by the net
tag in the subject) and I'm fine with it.
Thanks a lot.
--
MST
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH net 1/2] vhost: use mutex_lock_nested() in vhost_dev_lock_vqs()
2018-01-24 21:46 ` Michael S. Tsirkin
@ 2018-01-24 21:55 ` David Miller
0 siblings, 0 replies; 7+ messages in thread
From: David Miller @ 2018-01-24 21:55 UTC (permalink / raw)
To: mst; +Cc: netdev, linux-kernel, virtualization
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: Wed, 24 Jan 2018 23:46:19 +0200
> On Wed, Jan 24, 2018 at 04:38:30PM -0500, David Miller wrote:
>> From: Jason Wang <jasowang@redhat.com>
>> Date: Tue, 23 Jan 2018 17:27:25 +0800
>>
>> > We used to call mutex_lock() in vhost_dev_lock_vqs() which tries to
>> > hold mutexes of all virtqueues. This may confuse lockdep to report a
>> > possible deadlock because of trying to hold locks belong to same
>> > class. Switch to use mutex_lock_nested() to avoid false positive.
>> >
>> > Fixes: 6b1e6cc7855b0 ("vhost: new device IOTLB API")
>> > Reported-by: syzbot+dbb7c1161485e61b0241@syzkaller.appspotmail.com
>> > Signed-off-by: Jason Wang <jasowang@redhat.com>
>>
>> Michael, I see you ACK'd this, meaning that you're OK with these two
>> fixes going via my net tree?
>>
>> Thanks.
>
> Yes - this seems to be what Jason wanted (judging by the net
> tag in the subject) and I'm fine with it.
> Thanks a lot.
Great, not a problem, done.
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2018-01-24 21:55 UTC | newest]
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2018-01-23 9:27 [PATCH net 1/2] vhost: use mutex_lock_nested() in vhost_dev_lock_vqs() Jason Wang
2018-01-23 9:27 ` [PATCH net 2/2] vhost: do not try to access device IOTLB when not initialized Jason Wang
2018-01-23 15:58 ` Michael S. Tsirkin
2018-01-23 15:57 ` [PATCH net 1/2] vhost: use mutex_lock_nested() in vhost_dev_lock_vqs() Michael S. Tsirkin
2018-01-24 21:38 ` David Miller
2018-01-24 21:46 ` Michael S. Tsirkin
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