Messages in this thread Patch in this message | | | Date | Sun, 8 Jan 2012 03:51:09 -0800 | From | tip-bot for David Daney <> | Subject | [tip:perf/core] recordmcount: Fix handling of elf64 big-endian objects. |
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Commit-ID: 2e885057b7f75035f0b85e02f737891482815a81 Gitweb: http://git.kernel.org/tip/2e885057b7f75035f0b85e02f737891482815a81 Author: David Daney <david.daney@cavium.com> AuthorDate: Mon, 19 Dec 2011 17:42:42 -0800 Committer: Steven Rostedt <rostedt@goodmis.org> CommitDate: Fri, 6 Jan 2012 17:06:42 -0500
recordmcount: Fix handling of elf64 big-endian objects.
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.
Link: http://lkml.kernel.org/r/1324345362-12230-1-git-send-email-ddaney.cavm@gmail.com
Cc: stable@kernel.org # 3.0+ Signed-off-by: David Daney <david.daney@cavium.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> --- 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 */ succeed_file(); } 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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