64e5621a15
[ Upstream commit 09454fd0a4ce23cb3d8af65066c91a1bf27120dd ]
This reverts commit 19bda36c4299ce3d7e5bce10bebe01764a655a6d:
| ipv6: add mtu lock check in __ip6_rt_update_pmtu
|
| Prior to this patch, ipv6 didn't do mtu lock check in ip6_update_pmtu.
| It leaded to that mtu lock doesn't really work when receiving the pkt
| of ICMPV6_PKT_TOOBIG.
|
| This patch is to add mtu lock check in __ip6_rt_update_pmtu just as ipv4
| did in __ip_rt_update_pmtu.
The above reasoning is incorrect. IPv6 *requires* icmp based pmtu to work.
There's already a comment to this effect elsewhere in the kernel:
$ git grep -p -B1 -A3 'RTAX_MTU lock'
net/ipv6/route.c=4813=
static int rt6_mtu_change_route(struct fib6_info *f6i, void *p_arg)
...
/* In IPv6 pmtu discovery is not optional,
so that RTAX_MTU lock cannot disable it.
We still use this lock to block changes
caused by addrconf/ndisc.
*/
This reverts to the pre-4.9 behaviour.
Cc: Eric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Cc: Xin Long <lucien.xin@gmail.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Fixes: 19bda36c4299 ("ipv6: add mtu lock check in __ip6_rt_update_pmtu")
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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