• Yonghong Song's avatar
    tools/bpf: fix a selftest test_btf failure · 206dafb0
    Yonghong Song authored
    Commit 9c651127 ("selftests/btf: add initial BTF dedup tests")
    added dedup tests in test_btf.c.
    It broke the raw test:
     BTF raw test[71] (func proto (Bad arg name_off)):
        btf_raw_create:2905:FAIL Error getting string #65535, strs_cnt:1
    
    The test itself encodes invalid func_proto parameter name
    offset 0xffffFFFF as a negative test for the kernel.
    The above commit changed the meaning of that offset and
    resulted in a user space error.
      #define NAME_NTH(N) (0xffff0000 | N)
      #define IS_NAME_NTH(X) ((X & 0xffff0000) == 0xffff0000)
      #define GET_NAME_NTH_IDX(X) (X & 0x0000ffff)
    
    Currently, the kernel permits maximum name offset 0xffff.
    Set the test name off as 0x0fffFFFF to trigger the kernel
    verification failure.
    
    Cc: Andrii Nakryiko <andriin@fb.com>
    Fixes: 9c651127 ("selftests/btf: add initial BTF dedup tests")
    Signed-off-by: default avatarYonghong Song <yhs@fb.com>
    Acked-by: default avatarAndrii Nakryiko <andriin@fb.com>
    Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
    206dafb0
test_btf.c 163 KB