From: Jason Wang <jasowang@redhat.com>
To: mst@redhat.com, jasowang@redhat.com, linux-kernel@vger.kernel.org
Cc: virtualization@lists.linux-foundation.org, netdev@vger.kernel.org
Subject: [PATCH net 1/2] vhost: use mutex_lock_nested() in vhost_dev_lock_vqs()
Date: Tue, 23 Jan 2018 17:27:25 +0800 [thread overview]
Message-ID: <1516699646-7321-1-git-send-email-jasowang@redhat.com> (raw)
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
next reply other threads:[~2018-01-23 9:27 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-23 9:27 Jason Wang [this message]
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
2018-01-24 21:55 ` David Miller
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