[lkml]   [2012]   [Jan]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    Patch in this message
    Subject[073/129] recordmcount: Fix handling of elf64 big-endian objects.
    3.2-stable review patch.  If anyone has any objections, please let me know.

    Content-Length: 1330
    Lines: 39

    From: David Daney <>

    commit 2e885057b7f75035f0b85e02f737891482815a81 upstream.

    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 <>
    Signed-off-by: Steven Rostedt <>
    Signed-off-by: Greg Kroah-Hartman <>

    scripts/recordmcount.h | 2 +-
    1 file changed, 1 insertion(+), 1 deletion(-)

    --- a/scripts/recordmcount.h
    +++ b/scripts/recordmcount.h
    @@ -462,7 +462,7 @@ __has_rel_mcount(Elf_Shdr const *const r
    if (w(txthdr->sh_type) != SHT_PROGBITS ||
    - !(w(txthdr->sh_flags) & SHF_EXECINSTR))
    + !(_w(txthdr->sh_flags) & SHF_EXECINSTR))
    return NULL;
    return txtname;

     \ /
      Last update: 2012-01-24 03:51    [W:0.019 / U:1.584 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site