From: Jason Wang Date: Tue, 23 Jan 2018 09:27:25 +0000 (+0800) Subject: vhost: use mutex_lock_nested() in vhost_dev_lock_vqs() X-Git-Tag: v4.19~1792^2~3 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=e9cb4239134c860e5f92c75bf5321bd377bb505b;p=platform%2Fkernel%2Flinux-rpi.git 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: 6b1e6cc7855b0 ("vhost: new device IOTLB API") Reported-by: syzbot+dbb7c1161485e61b0241@syzkaller.appspotmail.com Signed-off-by: Jason Wang Acked-by: Michael S. Tsirkin Signed-off-by: David S. Miller --- 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)