[RFC PATCH bpf-next 0/2] test_bpf: Add an skb_segment test for a linear head_frag=0 skb whose gso_size was mangled

Following reports of skb_segment() hitting a BUG_ON when working on
GROed skbs which have their gso_size mangled (e.g. after a
bpf_skb_change_proto call), add a reproducer test that mimics the
input skbs that lead to the mentioned BUG_ON as in [1].

Currently, this new test *INDEED* hits the BUG_ON, therefore the final
patch is to be applied only after skb_segment is fixed.

When changing the gso_size of the test skb to its original value (+20
bytes) then the test passes successfully.

[1] https://lists.openwall.net/netdev/2019/08/26/110

Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Eric Dumazet <redacted>
Cc: Yonghong Song <redacted> 

Shmulik Ladkani (2):
  test_bpf: Refactor test_skb_segment() to allow testing skb_segment()
    on numerous different skbs
  test_bpf: Introduce 'gso_linear_no_head_frag' skb_segment test

 lib/test_bpf.c | 112 +++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 103 insertions(+), 9 deletions(-)

-- 
2.19.1