This is a note to let you know that I've just added the patch titled route: also update fnhe_genid when updating a route cache to the 4.4-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: route-also-update-fnhe_genid-when-updating-a-route-cache.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Tue Dec 12 13:38:50 CET 2017 From: Xin Long <lucien.xin@xxxxxxxxx> Date: Fri, 17 Nov 2017 14:27:18 +0800 Subject: route: also update fnhe_genid when updating a route cache From: Xin Long <lucien.xin@xxxxxxxxx> [ Upstream commit cebe84c6190d741045a322f5343f717139993c08 ] Now when ip route flush cache and it turn out all fnhe_genid != genid. If a redirect/pmtu icmp packet comes and the old fnhe is found and all it's members but fnhe_genid will be updated. Then next time when it looks up route and tries to rebind this fnhe to the new dst, the fnhe will be flushed due to fnhe_genid != genid. It causes this redirect/pmtu icmp packet acutally not to be applied. This patch is to also reset fnhe_genid when updating a route cache. Fixes: 5aad1de5ea2c ("ipv4: use separate genid for next hop exceptions") Acked-by: Hannes Frederic Sowa <hannes@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Xin Long <lucien.xin@xxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/ipv4/route.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -624,9 +624,12 @@ static void update_or_create_fnhe(struct struct fnhe_hash_bucket *hash; struct fib_nh_exception *fnhe; struct rtable *rt; + u32 genid, hval; unsigned int i; int depth; - u32 hval = fnhe_hashfun(daddr); + + genid = fnhe_genid(dev_net(nh->nh_dev)); + hval = fnhe_hashfun(daddr); spin_lock_bh(&fnhe_lock); @@ -649,6 +652,8 @@ static void update_or_create_fnhe(struct } if (fnhe) { + if (fnhe->fnhe_genid != genid) + fnhe->fnhe_genid = genid; if (gw) fnhe->fnhe_gw = gw; if (pmtu) { @@ -673,7 +678,7 @@ static void update_or_create_fnhe(struct fnhe->fnhe_next = hash->chain; rcu_assign_pointer(hash->chain, fnhe); } - fnhe->fnhe_genid = fnhe_genid(dev_net(nh->nh_dev)); + fnhe->fnhe_genid = genid; fnhe->fnhe_daddr = daddr; fnhe->fnhe_gw = gw; fnhe->fnhe_pmtu = pmtu; Patches currently in stable-queue which might be from lucien.xin@xxxxxxxxx are queue-4.4/route-update-fnhe_expires-for-redirect-when-the-fnhe-exists.patch queue-4.4/route-also-update-fnhe_genid-when-updating-a-route-cache.patch queue-4.4/sctp-use-the-right-sk-after-waking-up-from-wait_buf-sleep.patch queue-4.4/sctp-do-not-free-asoc-when-it-is-already-dead-in-sctp_sendmsg.patch