Re: [PATCH v2 net] ip6_gre: use skb_vlan_inet_prepare() instead of pskb_inet_may_pull()

On Wed, Jan 7, 2026 at 9:46 AM Florian Westphal [off-list ref] wrote:

Eric Dumazet [off-list ref] wrote:

quoted

On Tue, Jan 6, 2026 at 6:56 PM Jakub Kicinski [off-list ref] wrote:

quoted

On Tue,  6 Jan 2026 14:45:29 +0000 Eric Dumazet wrote:

quoted

v2: invert the conditions (Jakub)

Thanks! Much better now, but still failing
tools/testing/selftests/net/gre_gso.sh

TAP version 13
1..1
# timeout set to 3600
# selftests: net: gre_gso.sh
# 2.16 [+2.16]     TEST: GREv6/v4 - copy file w/ TSO                                   [ OK ]
# 3.16 [+1.01] 2026/01/06 10:32:57 socat[20546] W exiting on signal 15
# 3.17 [+0.01] 2026/01/06 10:32:57 socat[20546] W exiting on signal 15
# 3.17 [+0.00]     TEST: GREv6/v4 - copy file w/ GSO                                   [FAIL]
# 3.18 [+0.01] 2026/01/06 10:32:57 socat[20533] W exiting on signal 15
# 3.19 [+0.00]     TEST: GREv6/v6 - copy file w/ TSO                                   [ OK ]
# 4.19 [+1.00] 2026/01/06 10:32:59 socat[20559] W exiting on signal 15
# 4.19 [+0.01]     TEST: GREv6/v6 - copy file w/ GSO                                   [FAIL]
# 4.20 [+0.01] 2026/01/06 10:32:59 socat[20549] W exiting on signal 15
# 4.22 [+0.02] 2026/01/06 10:32:59 socat[20560] W exiting on signal 15
# 4.23 [+0.01]
# 4.23 [+0.00] Tests passed:   2
# 4.23 [+0.00] Tests failed:   2
not ok 1 selftests: net: gre_gso.sh # exit=1

https://netdev-ctrl.bots.linux.dev/logs/vmksft/net/results/461862/65-gre-gso-sh/stdout

For some reason I am unable to run this test from a virtme-ng instance.

I guess I wlll not make a new version of this patch, maybe Florian can
take over.

Its failing because nhoff is moved by 14 bytes, test passes after doing:

-       if (skb_vlan_inet_prepare(skb, false))
+       if (skb_vlan_inet_prepare(skb, true))

Thanks Florian.

I finally understood that my virtme-ng problem with this test is that
on my platform, /proc/sys/net/core/fb_tunnels_only_for_init_net was
set to 2

Tests have a hidden dependency against this sysctl.