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Commit e9cb4239 authored by Jason Wang's avatar Jason Wang Committed by David S. Miller
Browse files

vhost: use mutex_lock_nested() in vhost_dev_lock_vqs() 



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: 6b1e6cc7 ("vhost: new device IOTLB API")
Reported-by: default avatar <syzbot+dbb7c1161485e61b0241@syzkaller.appspotmail.com>
Signed-off-by: default avatarJason Wang <jasowang@redhat.com>
Acked-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent b7051cb8

drivers/vhost/vhost.c

+1 −1
Original line number Diff line number Diff line
@@ -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)