ipv6: set dst.obsolete when a cached route has expired
Now it doesn't check for the cached route expiration in ipv6's
dst_ops->check(), because it trusts dst_gc that would clean the
cached route up when it's expired.
The problem is in dst_gc, it would clean the cached route only
when it's refcount is 1. If some other module (like xfrm) keeps
holding it and the module only release it when dst_ops->check()
fails.
But without checking for the cached route expiration, .check()
may always return true. Meanwhile, without releasing the cached
route, dst_gc couldn't del it. It will cause this cached route
never to expire.
This patch is to set dst.obsolete with DST_OBSOLETE_KILL in .gc
when it's expired, and check obsolete != DST_OBSOLETE_FORCE_CHK
in .check.
Note that this is even needed when ipv6 dst_gc timer is removed
one day. It would set dst.obsolete in .redirect and .update_pmtu
instead, and check for cached route expiration when getting it,
just like what ipv4 route does.
Reported-by: Jianlin Shi <jishi@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 86fb241..2d0e779 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -440,7 +440,8 @@ static bool rt6_check_expired(const struct rt6_info *rt)
if (time_after(jiffies, rt->dst.expires))
return true;
} else if (rt->dst.from) {
- return rt6_check_expired((struct rt6_info *) rt->dst.from);
+ return rt->dst.obsolete != DST_OBSOLETE_FORCE_CHK ||
+ rt6_check_expired((struct rt6_info *)rt->dst.from);
}
return false;
}