net:gre_gso.sh in ubuntu_kernel_selftests failed on J-kvm

[Po-Hsu Lin]

This is not a regression, but a new failure found after resolving the missing socat command issue (bug 2000777)

Test failed with:
 Running 'make run_tests -C net TEST_PROGS=gre_gso.sh TEST_GEN_PROGS='' TEST_CUSTOM_PROGS='''
 make: Entering directory '/home/ubuntu/autotest/client/tmp/ubuntu_kernel_selftests/src/linux/tools/testing/selftests/net'
 make --no-builtin-rules ARCH=x86 -C ../../../.. headers_install
 make[1]: Entering directory '/home/ubuntu/autotest/client/tmp/ubuntu_kernel_selftests/src/linux'
   INSTALL ./usr/include
 make[1]: Leaving directory '/home/ubuntu/autotest/client/tmp/ubuntu_kernel_selftests/src/linux'
 TAP version 13
 1..1
 # selftests: net: gre_gso.sh
 # add tunnel "ip6gre0" failed: No such device
 # Cannot find device "gre1"
 # add tunnel "ip6gre0" failed: No such device
 # Cannot find device "gre1"
 # Cannot find device "gre1"
 # Cannot find device "gre1"
 # Cannot find device "gre1"
 # Cannot find device "gre1"
 # TEST: GREv6/v4 - copy file w/ TSO [FAIL]
 # TEST: GREv6/v4 - copy file w/ GSO [FAIL]
 # 2023/01/12 08:31:26 socat[65595] E connect(19, AF=10 [2001:0db8:0001:0000:0000:0000:0000:0002]:7777, 28): Network is unreachable
 # TEST: GREv6/v6 - copy file w/ TSO [FAIL]
 # 2023/01/12 08:31:26 socat[65599] E connect(19, AF=10 [2001:0db8:0001:0000:0000:0000:0000:0002]:7777, 28): Network is unreachable
 # TEST: GREv6/v6 - copy file w/ GSO [FAIL]
 #
 # Tests passed: 0
 # Tests failed: 4
 not ok 1 selftests: net: gre_gso.sh # exit=1

I think this would require CONFIG_IPV6_GRE to be enabled.