ACK/Cmnt: [REGRESSION][N][PATCH 0/1] Fix Upstream stable v6.6.122, v6.12.67, v6.12.68

[Stefan Bader]

On 15/04/2026 12:03, Manuel Diewald wrote:
> On Wed, Apr 15, 2026 at 12:40:13PM +0300, Mehmet Basaran wrote:
>> == Justification ==
>>
>> Impact:
>> The upstream stable v6.6.122, v6.12.67, v6.12.68 update included a
>> change to __ip6_tnl_rcv() which does not work for kernels <v6.13
>> (this might be important if the following is ever picked):
>>
>> f842901be344 "ip6_tunnel: use skb_vlan_inet_prepare() in __ip6_tnl_rcv()"
>>
>> Above patch replaces pskb_inet_may_pull() with skb_vlan_inet_prepare().
>> The problem is that around v6.13 there was
>>
>> "net: tunnel: make skb_vlan_inet_prepare() return drop reasons"
>>
>> which changes return values of skb_vlan_inet_prepare(). Before a non
>> zero return code meant success while after it is the opposite.
>>
>> Fix:
>> Instead of pulling another dependency the proposed fix changes usage to
>> other callers of skb_vlan_inet_prepare() in v6.8
>> (bareudp.c/geneve.c/vxlan_core.c).
>>
>> Testcase:
>> Running the ubuntu_kselftests_net:net:l2_tos_ttl_inherit.sh fail (timeout)
>> without the fix. After applying the test passes again.
>>
>> Mehmet Basaran (1):
>>    UBUNTU: SAUCE: Fix skb_vlan_inet_prepare() usage
>>
>>   net/ipv6/ip6_tunnel.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> -- 
>> 2.43.0
>>
>>
>> -- 
>> kernel-team mailing list
>> kernel-team at lists.ubuntu.com
>> https://lists.ubuntu.com/mailman/listinfo/kernel-team
> 
> I think we should probably submit this to upstream, too.

I did send it for 5.15 (with no reaction). For Noble it depends whether 
the patch came from before 6.13 or not. Because around then the function 
changed to return an int.

-Stefan

> 
> Acked-by: Manuel Diewald <manuel.diewald at canonical.com>
> 
> 

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