Patch "virtio-net: add a missing synchronize_net()" has been added to the 4.4-stable tree

Patch "virtio-net: add a missing synchronize_net()" has been added to the 4.4-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    virtio-net: add a missing synchronize_net()

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     virtio-net-add-a-missing-synchronize_net.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From foo@baz Thu Dec  8 07:18:57 CET 2016
From: Eric Dumazet <edumazet@google.com>
Date: Tue, 15 Nov 2016 22:24:12 -0800
Subject: virtio-net: add a missing synchronize_net()

From: Eric Dumazet <edumazet@google.com>


[ Upstream commit 963abe5c8a0273a1cf5913556da1b1189de0e57a ]

It seems many drivers do not respect napi_hash_del() contract.

When napi_hash_del() is used before netif_napi_del(), an RCU grace
period is needed before freeing NAPI object.

Fixes: 91815639d880 ("virtio-net: rx busy polling support")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Jason Wang <jasowang@redhat.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/virtio_net.c |    5 +++++
 1 file changed, 5 insertions(+)

--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -1465,6 +1465,11 @@ static void virtnet_free_queues(struct v
 		netif_napi_del(&vi->rq[i].napi);
 	}
 
+	/* We called napi_hash_del() before netif_napi_del(),
+	 * we need to respect an RCU grace period before freeing vi->rq
+	 */
+	synchronize_net();
+
 	kfree(vi->rq);
 	kfree(vi->sq);
 }


Patches currently in stable-queue which might be from edumazet@google.com are

queue-4.4/virtio-net-add-a-missing-synchronize_net.patch
queue-4.4/net-dccp-fix-use-after-free-in-dccp_invalid_packet.patch
queue-4.4/net-avoid-signed-overflows-for-so_-snd-rcv-bufforce.patch
queue-4.4/packet-fix-race-condition-in-packet_set_ring.patch