From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-Id: <20120124023930.389023610@clark.kroah.org> Date: Mon, 23 Jan 2012 18:34:53 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, David Daney , Steven Rostedt Subject: [073/129] recordmcount: Fix handling of elf64 big-endian objects. In-Reply-To: <20120124024041.GA18422@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: 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. Link: http://lkml.kernel.org/r/1324345362-12230-1-git-send-email-ddaney.cavm@gmail.com 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 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; }