tree 9a4234c9f218b9ab2caa0c3cc5a1f555d7e9ea86
parent 80c1c8322c331586a86e58d3f95026a1265ab396
author Jason Wang <jasowang@redhat.com> 1516699645 +0800
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> 1519553139 +0100

vhost: use mutex_lock_nested() in vhost_dev_lock_vqs()

commit e9cb4239134c860e5f92c75bf5321bd377bb505b upstream.

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>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>