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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org,
        syzbot+eb17c6162478cc50632c@syzkaller.appspotmail.com,
        "Jason Wang" <jasowang@redhat.com>,
        "David S. Miller" <davem@davemloft.net>
Date:   Thu, 07 Jun 2018 15:05:21 +0100
Message-ID: <lsq.1528380321.546621487@decadent.org.uk>
Subject: [PATCH 3.16 176/410] vhost_net: stop device during reset owner
In-Reply-To: <lsq.1528380320.647747352@decadent.org.uk>
Sender: linux-kernel-owner@vger.kernel.org
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3.16.57-rc1 review patch.  If anyone has any objections, please let me know.

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

From: Jason Wang <jasowang@redhat.com>

commit 4cd879515d686849eec5f718aeac62a70b067d82 upstream.

We don't stop device before reset owner, this means we could try to
serve any virtqueue kick before reset dev->worker. This will result a
warn since the work was pending at llist during owner resetting. Fix
this by stopping device during owner reset.

Reported-by: syzbot+eb17c6162478cc50632c@syzkaller.appspotmail.com
Fixes: 3a4d5c94e9593 ("vhost_net: a kernel-level virtio server")
Signed-off-by: Jason Wang <jasowang@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 drivers/vhost/net.c | 1 +
 1 file changed, 1 insertion(+)

--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -1009,6 +1009,7 @@ static long vhost_net_reset_owner(struct
 	}
 	vhost_net_stop(n, &tx_sock, &rx_sock);
 	vhost_net_flush(n);
+	vhost_dev_stop(&n->dev);
 	vhost_dev_reset_owner(&n->dev, memory);
 	vhost_net_vq_reset(n);
 done: