This is a note to let you know that I've just added the patch titled ipv6: do not use RT_TOS for IPv6 flowlabel to the 5.19-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: ipv6-do-not-use-rt_tos-for-ipv6-flowlabel.patch and it can be found in the queue-5.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From ab7e2e0dfa5d37540ab1dc5376e9a2cb9188925d Mon Sep 17 00:00:00 2001 From: Matthias May <matthias.may@xxxxxxxxxxxx> Date: Fri, 5 Aug 2022 21:19:06 +0200 Subject: ipv6: do not use RT_TOS for IPv6 flowlabel From: Matthias May <matthias.may@xxxxxxxxxxxx> commit ab7e2e0dfa5d37540ab1dc5376e9a2cb9188925d upstream. According to Guillaume Nault RT_TOS should never be used for IPv6. Quote: RT_TOS() is an old macro used to interprete IPv4 TOS as described in the obsolete RFC 1349. It's conceptually wrong to use it even in IPv4 code, although, given the current state of the code, most of the existing calls have no consequence. But using RT_TOS() in IPv6 code is always a bug: IPv6 never had a "TOS" field to be interpreted the RFC 1349 way. There's no historical compatibility to worry about. Fixes: 571912c69f0e ("net: UDP tunnel encapsulation module for tunnelling different protocols like MPLS, IP, NSH etc.") Acked-by: Guillaume Nault <gnault@xxxxxxxxxx> Signed-off-by: Matthias May <matthias.may@xxxxxxxxxxxx> Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/ipv6/ip6_output.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -1311,8 +1311,7 @@ struct dst_entry *ip6_dst_lookup_tunnel( fl6.daddr = info->key.u.ipv6.dst; fl6.saddr = info->key.u.ipv6.src; prio = info->key.tos; - fl6.flowlabel = ip6_make_flowinfo(RT_TOS(prio), - info->key.label); + fl6.flowlabel = ip6_make_flowinfo(prio, info->key.label); dst = ipv6_stub->ipv6_dst_lookup_flow(net, sock->sk, &fl6, NULL); Patches currently in stable-queue which might be from matthias.may@xxxxxxxxxxxx are queue-5.19/geneve-do-not-use-rt_tos-for-ipv6-flowlabel.patch queue-5.19/mlx5-do-not-use-rt_tos-for-ipv6-flowlabel.patch queue-5.19/ipv6-do-not-use-rt_tos-for-ipv6-flowlabel.patch queue-5.19/vxlan-do-not-use-rt_tos-for-ipv6-flowlabel.patch