[PATCH 0/2] [RESEND] Fold checksum at the end of bpf_csum_diff and fix

[Paolo Pisati <p.pisati@gmail.com>]

From: Paolo Pisati <paolo.pisati@canonical.com>

After applying patch 0001, all checksum implementations i could test (x86-64, arm64 and
arm), now agree on the return value.

Patch 0002 fix the expected return value for test #13: i did the calculation manually,
and it correspond.

Unfortunately, after applying patch 0001, other test cases now fail in
test_verifier:

$ sudo ./tools/testing/selftests/bpf/test_verifier
...
#417/p helper access to variable memory: size = 0 allowed on NULL (ARG_PTR_TO_MEM_OR_NULL) FAIL retval 65535 != 0 
#419/p helper access to variable memory: size = 0 allowed on != NULL stack pointer (ARG_PTR_TO_MEM_OR_NULL) FAIL retval 65535 != 0 
#423/p helper access to variable memory: size possible = 0 allowed on != NULL packet pointer (ARG_PTR_TO_MEM_OR_NULL) FAIL retval 65535 != 0 
...
Summary: 1500 PASSED, 0 SKIPPED, 3 FAILED

And there are probably other fallouts in other selftests - someone familiar
should take a look before applying these patches.

Paolo Pisati (2):
  bpf: bpf_csum_diff: fold the checksum before returning the
    value
  bpf, selftest: fix checksum value for test #13

 net/core/filter.c                                   | 2 +-
 tools/testing/selftests/bpf/verifier/array_access.c | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

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2.17.1