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author | David Daney <ddaney@caviumnetworks.com> | 2010-07-09 14:52:05 -0700 |
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committer | Steven Rostedt <rostedt@goodmis.org> | 2010-07-22 14:55:43 -0400 |
commit | a484e54fae891703cbe1c9ec1b536605f11f5482 (patch) | |
tree | 5823d13ad3118c642a90af4df852077f20f5e6c4 | |
parent | 9849ed4d72251d273524efb8b70be0be9aecb1df (diff) | |
download | linux-a484e54fae891703cbe1c9ec1b536605f11f5482.tar.gz linux-a484e54fae891703cbe1c9ec1b536605f11f5482.tar.bz2 linux-a484e54fae891703cbe1c9ec1b536605f11f5482.zip |
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 $mcount_regex to only match on these.
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Acked-by: Wu Zhangjin <wuzhangjin@gmail.com>
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
LKML-Reference: <1278712325-12050-1-git-send-email-ddaney@caviumnetworks.com>
Cc: Li Hong <lihong.hi@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Matt Fleming <matt@console-pimps.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
-rwxr-xr-x | scripts/recordmcount.pl | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/scripts/recordmcount.pl b/scripts/recordmcount.pl index f3c9c0a90b98..0171060b5fd6 100755 --- a/scripts/recordmcount.pl +++ b/scripts/recordmcount.pl @@ -326,7 +326,7 @@ if ($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\$"; } |