net: vrf: Reset rt6i_idev in local dst after put

[ Upstream commit 3dc857f0e8fc22610a59cbb346ba62c6e921863f ]

The VRF driver takes a reference to the inet6_dev on the VRF device for
its rt6_local dst when handling local traffic through the VRF device as
a loopback. When the device is deleted the driver does a put on the idev
but does not reset rt6i_idev in the rt6_info struct. When the dst is
destroyed, dst_destroy calls ip6_dst_destroy which does a second put for
what is essentially the same reference causing it to be prematurely freed.
Reset rt6i_idev after the put in the vrf driver.

Fixes: b4869aa2f881e ("net: vrf: ipv6 support for local traffic to
                       local addresses")
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/net/vrf.c b/drivers/net/vrf.c
index bc744ac..a2afb8e 100644 (file)
--- a/drivers/net/vrf.c
+++ b/drivers/net/vrf.c
@@ -467,8 +467,10 @@ static void vrf_rt6_release(struct net_device *dev, struct net_vrf *vrf)
        }
 
        if (rt6_local) {
-               if (rt6_local->rt6i_idev)
+               if (rt6_local->rt6i_idev) {
                        in6_dev_put(rt6_local->rt6i_idev);
+                       rt6_local->rt6i_idev = NULL;
+               }
 
                dst = &rt6_local->dst;
                dev_put(dst->dev);