Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754267Ab0GIVwl (ORCPT ); Fri, 9 Jul 2010 17:52:41 -0400 Received: from mail3.caviumnetworks.com ([12.108.191.235]:15335 "EHLO mail3.caviumnetworks.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751817Ab0GIVwk (ORCPT ); Fri, 9 Jul 2010 17:52:40 -0400 From: David Daney To: rostedt@goodmis.org Cc: linux-kernel@vger.kernel.org, linux-mips@linux-mips.org, David Daney , Li Hong , Ingo Molnar , Matt Fleming , Ralf Baechle Subject: [PATCH] tracing: recordmcount.pl: Fix $mcount_regex for MIPS. Date: Fri, 9 Jul 2010 14:52:05 -0700 Message-Id: <1278712325-12050-1-git-send-email-ddaney@caviumnetworks.com> X-Mailer: git-send-email 1.6.6.1 X-OriginalArrivalTime: 09 Jul 2010 21:52:39.0815 (UTC) FILETIME=[0D02C970:01CB1FB1] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2028 Lines: 50 I found this issue in a locally patched 2.6.32.x, current kernels have moved the offending code to an __init function which is skipped by recordmcount.pl, so the bug is not currently being exercised. However, I think the patch is still a good idea, to avoid future problems if _mcount were to ever have its address taken in normal code. This is what I originally saw: Although arch/mips/kernel/ftrace.c is built without -pg, and thus contains no calls to _mcount, it does use the address of _mcount in ftrace_make_nop(). This was causing relocations to be emitted for _mcount which recordmcount.pl erronously took to be _mcount call sites. The result was that the text of ftrace_make_nop() would be patched with garbage leading to a system crash. In non-module code, all _mcount call sites will have R_MIPS_26 relocations, so we restrict $mcount_regex to only match on these. Signed-off-by: David Daney Cc: Steven Rostedt Cc: Li Hong Cc: Ingo Molnar Cc: Matt Fleming Cc: Ralf Baechle --- scripts/recordmcount.pl | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/scripts/recordmcount.pl b/scripts/recordmcount.pl index f3c9c0a..0171060 100755 --- a/scripts/recordmcount.pl +++ b/scripts/recordmcount.pl @@ -326,7 +326,7 @@ if ($arch eq "x86_64") { # 14: R_MIPS_NONE *ABS* # 18: 00020021 nop if ($is_module eq "0") { - $mcount_regex = "^\\s*([0-9a-fA-F]+):.*\\s_mcount\$"; + $mcount_regex = "^\\s*([0-9a-fA-F]+): R_MIPS_26\\s+_mcount\$"; } else { $mcount_regex = "^\\s*([0-9a-fA-F]+): R_MIPS_HI16\\s+_mcount\$"; } -- 1.6.6.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/