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authorJason Wang <jasowang@redhat.com>2018-01-23 12:27:25 +0300
committerDavid S. Miller <davem@davemloft.net>2018-01-25 00:55:37 +0300
commite9cb4239134c860e5f92c75bf5321bd377bb505b (patch)
tree07574c95ec8663139c964f4355c559ee27b379f8
parentb7051cb8dadd69f85da5989017af2bb35b418950 (diff)
downloadlinux-e9cb4239134c860e5f92c75bf5321bd377bb505b.tar.xz
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 <jasowang@redhat.com> Acked-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/vhost/vhost.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 33ac2b186b85..549771a0cd8b 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)