Fix for crash seen with Open Stack (rhbz 1361414)

kernel.spec

@@ -652,6 +652,9 @@ Patch841: audit-fix-a-double-fetch-in-audit_log_single_execve_arg.patch
 Patch842: kvm-ppc-Book3S-HV-Pull-out-TM-state-save.patch
 Patch843: kvm-ppc-Book3S-HV-Save-restore-TM-state.patch
 
+#rhbz 1361414
+Patch844: openstack_fix.patch
+
 # END OF PATCH DEFINITIONS
 
 %endif
@@ -2177,6 +2180,9 @@ fi
 #
 # 
 %changelog
+* Thu Aug 11 2016 Laura Abbott <labbott@fedoraproject.org>
+- Fix for crash seen with Open Stack (rhbz 1361414)
+
 * Wed Aug 10 2016 Laura Abbott <labbott@fedoraproject.org> - 4.6.6-300
 - Linux v4.6.6
 

openstack_fix.patch

@@ -0,0 +1,53 @@
+From 5ef9f289c4e698054e5687edb54f0da3cdc9173a Mon Sep 17 00:00:00 2001
+From: Ian Wienand <iwienand@redhat.com>
+Date: Wed, 3 Aug 2016 15:44:57 +1000
+Subject: OVS: Ignore negative headroom value
+
+net_device->ndo_set_rx_headroom (introduced in
+871b642adebe300be2e50aa5f65a418510f636ec) says
+
+  "Setting a negtaive value reset the rx headroom
+   to the default value".
+
+It seems that the OVS implementation in
+3a927bc7cf9d0fbe8f4a8189dd5f8440228f64e7 overlooked this and sets
+dev->needed_headroom unconditionally.
+
+This doesn't have an immediate effect, but can mess up later
+LL_RESERVED_SPACE calculations, such as done in
+net/ipv6/mcast.c:mld_newpack.  For reference, this issue was found
+from a skb_panic raised there after the length calculations had given
+the wrong result.
+
+Note the other current users of this interface
+(drivers/net/tun.c:tun_set_headroom and
+drivers/net/veth.c:veth_set_rx_headroom) are both checking this
+correctly thus need no modification.
+
+Thanks to Ben for some pointers from the crash dumps!
+
+Cc: Benjamin Poirier <bpoirier@suse.com>
+Cc: Paolo Abeni <pabeni@redhat.com>
+Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1361414
+Signed-off-by: Ian Wienand <iwienand@redhat.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+---
+ net/openvswitch/vport-internal_dev.c | 2 +-
+ 1 file changed, 1 insertion(+), 1 deletion(-)
+
+diff --git a/net/openvswitch/vport-internal_dev.c b/net/openvswitch/vport-internal_dev.c
+index 434e04c..95c3614 100644
+--- a/net/openvswitch/vport-internal_dev.c
++++ b/net/openvswitch/vport-internal_dev.c
+@@ -140,7 +140,7 @@ internal_get_stats(struct net_device *dev, struct rtnl_link_stats64 *stats)
+ 
+ static void internal_set_rx_headroom(struct net_device *dev, int new_hr)
+ {
+-	dev->needed_headroom = new_hr;
++	dev->needed_headroom = new_hr < 0 ? 0 : new_hr;
+ }
+ 
+ static const struct net_device_ops internal_dev_netdev_ops = {
+-- 
+cgit v0.12
+