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authorDavid Daney <ddaney@caviumnetworks.com>2010-07-09 14:52:05 -0700
committerSteven Rostedt <rostedt@goodmis.org>2010-07-22 14:55:43 -0400
commita484e54fae891703cbe1c9ec1b536605f11f5482 (patch)
tree5823d13ad3118c642a90af4df852077f20f5e6c4 /scripts/recordmcount.pl
parent9849ed4d72251d273524efb8b70be0be9aecb1df (diff)
downloadvexpress-lsk-a484e54fae891703cbe1c9ec1b536605f11f5482.tar.gz
tracing: Fix $mcount_regex for MIPS in recordmcount.pl
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 $mcount_regex to only match on these. Acked-by: Ralf Baechle <ralf@linux-mips.org> Acked-by: Wu Zhangjin <wuzhangjin@gmail.com> Signed-off-by: David Daney <ddaney@caviumnetworks.com> LKML-Reference: <1278712325-12050-1-git-send-email-ddaney@caviumnetworks.com> Cc: Li Hong <lihong.hi@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Matt Fleming <matt@console-pimps.org> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'scripts/recordmcount.pl')
-rwxr-xr-xscripts/recordmcount.pl2
1 files changed, 1 insertions, 1 deletions
diff --git a/scripts/recordmcount.pl b/scripts/recordmcount.pl
index f3c9c0a90b9..0171060b5fd 100755
--- a/scripts/recordmcount.pl
+++ b/scripts/recordmcount.pl
@@ -326,7 +326,7 @@ if ($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\$";
}