From 1e2ea8ad37be25a7cdcc974945935829d534d5d3 Mon Sep 17 00:00:00 2001 From: Xin Long Date: Sat, 26 Aug 2017 20:10:10 +0800 Subject: [PATCH] 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 Signed-off-by: Xin Long Acked-by: Hannes Frederic Sowa Signed-off-by: David S. Miller --- net/ipv6/ip6_fib.c | 4 +++- net/ipv6/route.c | 3 ++- 2 files changed, 5 insertions(+), 2 deletions(-) diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c index 10b4b1f8b838..e1c85bb4eac0 100644 --- a/net/ipv6/ip6_fib.c +++ b/net/ipv6/ip6_fib.c @@ -1795,8 +1795,10 @@ static int fib6_age(struct rt6_info *rt, void *arg) } gc_args->more++; } else if (rt->rt6i_flags & RTF_CACHE) { + if (time_after_eq(now, rt->dst.lastuse + gc_args->timeout)) + rt->dst.obsolete = DST_OBSOLETE_KILL; if (atomic_read(&rt->dst.__refcnt) == 1 && - time_after_eq(now, rt->dst.lastuse + gc_args->timeout)) { + rt->dst.obsolete == DST_OBSOLETE_KILL) { RT6_TRACE("aging clone %p\n", rt); return -1; } else if (rt->rt6i_flags & RTF_GATEWAY) { diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 86fb2411e2bd..2d0e7798c793 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; } -- 2.20.1