Patch "ipv6: Check rt->dst.from for the DST_NOCACHE route" has been added to the 4.3-stable tree

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

    ipv6: Check rt->dst.from for the DST_NOCACHE route

to the 4.3-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:
ipv6-check-rt-dst.from-for-the-dst_nocache-route.patch
and it can be found in the queue-4.3 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Martin KaFai Lau <[email protected]>
Date: Wed, 11 Nov 2015 11:51:08 -0800
Subject: ipv6: Check rt->dst.from for the DST_NOCACHE route

From: Martin KaFai Lau <[email protected]>

[ Upstrem commit 02bcf4e082e4dc634409a6a6cb7def8806d6e5e6 ]

All DST_NOCACHE rt6_info used to have rt->dst.from set to its parent.

After commit 8e3d5be73681 ("ipv6: Avoid double dst_free"), DST_NOCACHE is also set to rt6_info which does not have a parent (i.e. rt->dst.from is NULL).

This patch catches the rt->dst.from == NULL case.

---
 include/net/ip6_fib.h |    3 ++-
 net/ipv6/route.c      |    3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

@@ -167,7 +167,8 @@ static inline void rt6_update_expires(st
 
 static inline u32 rt6_get_cookie(const struct rt6_info *rt)
 {
-	if (rt->rt6i_flags & RTF_PCPU || unlikely(rt->dst.flags & DST_NOCACHE))
+	if (rt->rt6i_flags & RTF_PCPU ||
+	    (unlikely(rt->dst.flags & DST_NOCACHE) && rt->dst.from))
 		rt = (struct rt6_info *)(rt->dst.from);
 
 	return rt->rt6i_node ? rt->rt6i_node->fn_sernum : 0;

@@ -1299,7 +1299,8 @@ static struct dst_entry *ip6_dst_check(s
 
 	rt6_dst_from_metrics_check(rt);
 
-	if ((rt->rt6i_flags & RTF_PCPU) || unlikely(dst->flags & DST_NOCACHE))
+	if (rt->rt6i_flags & RTF_PCPU ||
+	    (unlikely(dst->flags & DST_NOCACHE) && rt->dst.from))
 		return rt6_dst_from_check(rt, cookie);
 	else
 		return rt6_check(rt, cookie);

Patches currently in stable-queue which might be from [email protected] are

queue-4.3/ipv6-check-rt-dst.from-for-the-dst_nocache-route.patch queue-4.3/ipv6-avoid-creating-rtf_cache-from-a-rt-that-is-not-managed-by-fib6-tree.patch queue-4.3/ipv6-check-expire-on-dst_nocache-route.patch queue-4.3/net-ip6_tunnel-fix-dst-leak.patch