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    Subject[PATCH] recordmcount: Fix handling of elf64 big-endian objects.
    From: David Daney <>

    In ELF64, the sh_flags field is 64-bits wide. recordmcount was
    erroneously treating it as a 32-bit wide field. For little endian
    objects this works because the flags of interest (SHF_EXECINSTR)
    reside in the lower 32 bits of the word, and you get the same result
    with either a 32-bit or 64-bit read. Big endian objects on the
    other hand do not work at all with this error.

    The fix: Correctly treat sh_flags as 64-bits wide in elf64 objects.

    The symptom I observed was that my
    __start_mcount_loc..__stop_mcount_loc was empty even though ftrace
    function tracing was enabled.

    Signed-off-by: David Daney <>
    scripts/recordmcount.h | 2 +-
    1 files changed, 1 insertions(+), 1 deletions(-)

    diff --git a/scripts/recordmcount.h b/scripts/recordmcount.h
    index f40a6af6..54e35c1 100644
    --- a/scripts/recordmcount.h
    +++ b/scripts/recordmcount.h
    @@ -462,7 +462,7 @@ __has_rel_mcount(Elf_Shdr const *const relhdr, /* is SHT_REL or SHT_RELA */
    if (w(txthdr->sh_type) != SHT_PROGBITS ||
    - !(w(txthdr->sh_flags) & SHF_EXECINSTR))
    + !(_w(txthdr->sh_flags) & SHF_EXECINSTR))
    return NULL;
    return txtname;

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      Last update: 2011-12-20 02:45    [W:0.020 / U:3.568 seconds]
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