linux-kernel - [PATCH 4.9 001/145] vhost: use mutex_lock_nested() in vhost_dev_lock

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20180223170724.846027079@linuxfoundation.org>
Date:   Fri, 23 Feb 2018 19:25:07 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org,
        syzbot+dbb7c1161485e61b0241@...kaller.appspotmail.com,
        Jason Wang <jasowang@...hat.com>,
        "Michael S. Tsirkin" <mst@...hat.com>,
        "David S. Miller" <davem@...emloft.net>
Subject: [PATCH 4.9 001/145] vhost: use mutex_lock_nested() in vhost_dev_lock_vqs()

4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jason Wang <jasowang@...hat.com>

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@...kaller.appspotmail.com
Signed-off-by: Jason Wang <jasowang@...hat.com>
Acked-by: Michael S. Tsirkin <mst@...hat.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/vhost/vhost.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -849,7 +849,7 @@ static void vhost_dev_lock_vqs(struct vh
 {
 	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)