Re: ipv6: BUG: unable to handle kernel paging request at 0000000101bca2be

[Eric Dumazet <eric.dumazet@gmail.com>]

On Sat, 2012-07-28 at 21:08 +0200, Eric Dumazet wrote:

> This looks like an error coming from commit
> 1716a96101c49186bb0b8491922fd3e69030235f
> (ipv6: fix problem with expired dst cache)
> 
> dst_release() is called with a bogus dst pointer : 0000000101bca23e
> 
> rt6_clean_expires() seems to be called where it shouldnt.
> 
> Could you try reverting it ?
> 

Or try following patch instead :

diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h
index 0ae759a..a85a865 100644
--- a/include/net/ip6_fib.h
+++ b/include/net/ip6_fib.h
@@ -123,13 +123,18 @@ static inline struct inet6_dev *ip6_dst_idev(struct dst_entry *dst)
 	return ((struct rt6_info *)dst)->rt6i_idev;
 }
 
+static inline void __rt6_clean_expires(struct rt6_info *rt)
+{
+	rt->rt6i_flags &= ~RTF_EXPIRES;
+	rt->dst.from = NULL;
+}
+
 static inline void rt6_clean_expires(struct rt6_info *rt)
 {
 	if (!(rt->rt6i_flags & RTF_EXPIRES) && rt->dst.from)
 		dst_release(rt->dst.from);
 
-	rt->rt6i_flags &= ~RTF_EXPIRES;
-	rt->dst.from = NULL;
+	__rt6_clean_expires(rt);
 }
 
 static inline void rt6_set_expires(struct rt6_info *rt, unsigned long expires)
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index becb048..965f315 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -969,7 +969,7 @@ struct dst_entry *ip6_blackhole_route(struct net *net, struct dst_entry *dst_ori
 
 		rt->rt6i_gateway = ort->rt6i_gateway;
 		rt->rt6i_flags = ort->rt6i_flags;
-		rt6_clean_expires(rt);
+		__rt6_clean_expires(rt);
 		rt->rt6i_metric = 0;
 
 		memcpy(&rt->rt6i_dst, &ort->rt6i_dst, sizeof(struct rt6key));
@@ -1305,7 +1305,7 @@ int ip6_route_add(struct fib6_config *cfg)
 		rt6_set_expires(rt, jiffies +
 				clock_t_to_jiffies(cfg->fc_expires));
 	else
-		rt6_clean_expires(rt);
+		__rt6_clean_expires(rt);
 
 	if (cfg->fc_protocol == RTPROT_UNSPEC)
 		cfg->fc_protocol = RTPROT_BOOT;
@@ -1837,7 +1837,7 @@ static struct rt6_info *ip6_rt_copy(struct rt6_info *ort,
 		    (RTF_DEFAULT | RTF_ADDRCONF))
 			rt6_set_from(rt, ort);
 		else
-			rt6_clean_expires(rt);
+			__rt6_clean_expires(rt);
 		rt->rt6i_metric = 0;
 
 #ifdef CONFIG_IPV6_SUBTREES