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Subject[PATCH] scripts: script from kerneloops.org to pretty print oops dumps
Hi,

I had this script lying around (used on kerneloops.org in a slightly modified form,
where I use a database as input rather than stdin). I think it's a useful tool,
at least I find it extremely useful in turning oopses into an "oh duh yes there"
experience...

I know it's in perl, and I know I suck at writing good perl. So I welcome all feedback I
can get... both on the perl and on the usefulness of having this script.


From 260d3f2246a4fe92f4ec633db82ab44605654d4f Mon Sep 17 00:00:00 2001
From: Arjan van de Ven <arjan@linux.intel.com>
Date: Wed, 5 Nov 2008 19:00:36 -0800
Subject: [PATCH] scripts: script from kerneloops.org to pretty print oops dumps

We're strugling all the time to figure out where the code came from
that oopsed.. The script below (a adaption from a script used by kerneloops.org)
can help developers quite a bit, at least for non-module cases.

It works and looks like this:

[/home/arjan/linux]$ dmesg | perl scripts/markup_code.pl vmlinux
{
struct agp_memory *memory;

memory = agp_allocate_memory(agp_bridge, pg_count, type);
c055c10f: 89 c2 mov %eax,%edx
if (memory == NULL)
c055c111: 74 19 je c055c12c <agp_allocate_memory_wrap+0x30>
/* This function must only be called when current_controller != NULL */
static void agp_insert_into_pool(struct agp_memory * temp)
{
struct agp_memory *prev;

prev = agp_fe.current_controller->pool;
c055c113: a1 ec dc 8f c0 mov 0xc08fdcec,%eax
*c055c118: 8b 40 10 mov 0x10(%eax),%eax <----- faulting instruction

if (prev != NULL) {
c055c11b: 85 c0 test %eax,%eax
c055c11d: 74 05 je c055c124 <agp_allocate_memory_wrap+0x28>
prev->prev = temp;
c055c11f: 89 50 04 mov %edx,0x4(%eax)
temp->next = prev;
c055c122: 89 02 mov %eax,(%edx)
}
agp_fe.current_controller->pool = temp;
c055c124: a1 ec dc 8f c0 mov 0xc08fdcec,%eax
c055c129: 89 50 10 mov %edx,0x10(%eax)
if (memory == NULL)
return NULL;

agp_insert_into_pool(memory);

so in this case, we faulted while dereferencing agp_fe.current_controller pointer, and we get to see
exactly which function and line it affects... Personally I find this very useful, and I can
see value for having this script in the kernel for more-than-just-me to use.

Caveats:
* It only works for oopses not-in-modules
* It only works nicely for kernels compiled with CONFIG_DEBUG_INFO
* It's not very fast.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
---
scripts/markup_oops.pl | 165 ++++++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 165 insertions(+), 0 deletions(-)
create mode 100644 scripts/markup_oops.pl

diff --git a/scripts/markup_oops.pl b/scripts/markup_oops.pl
new file mode 100644
index 0000000..c8a2200
--- /dev/null
+++ b/scripts/markup_oops.pl
@@ -0,0 +1,165 @@
+#!/usr/bin/perl -w
+
+# Copyright 2008, Intel Corporation
+#
+# This file is part of the Linux kernel
+#
+# This program file is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation; version 2 of the License.
+#
+# Authors:
+# Arjan van de Ven <arjan@linux.intel.com>
+
+
+my $vmlinux_name = $ARGV[0];
+
+#
+# Step 1: Parse the oops to find the EIP value
+#
+
+my $target = "0";
+while (<STDIN>) {
+ if ($_ =~ /EIP: 0060:\[\<([a-z0-9]+)\>\]/) {
+ $target = $1;
+ }
+}
+
+if ($target =~ /^f8/) {
+ print "This script does not work on modules ... \n";
+ exit;
+}
+
+if ($target eq "0") {
+ print "No oops found!\n";
+ print "Usage: \n";
+ print " dmesg | perl scripts/markup_oops.pl vmlinux\n";
+ exit;
+}
+
+my $counter = 0;
+my $state = 0;
+my $center = 0;
+my @lines;
+
+sub InRange {
+ my ($address, $target) = @_;
+ my $ad = "0x".$address;
+ my $ta = "0x".$target;
+ my $delta = hex($ad) - hex($ta);
+
+ if (($delta > -4096) && ($delta < 4096)) {
+ return 1;
+ }
+ return 0;
+}
+
+
+
+# first, parse the input into the lines array, but to keep size down,
+# we only do this for 4Kb around the sweet spot
+
+my $filename;
+
+open(FILE, "objdump -dS $vmlinux_name |") || die "Cannot start objdump";
+
+while (<FILE>) {
+ my $line = $_;
+ chomp($line);
+ if ($state == 0) {
+ if ($line =~ /^([a-f0-9]+)\:/) {
+ if (InRange($1, $target)) {
+ $state = 1;
+ }
+ }
+ } else {
+ if ($line =~ /^([a-f0-9][a-f0-9][a-f0-9][a-f0-9][a-f0-9][a-f0-9]+)\:/) {
+ my $val = $1;
+ if (!InRange($val, $target)) {
+ last;
+ }
+ if ($val eq $target) {
+ $center = $counter;
+ }
+ }
+ $lines[$counter] = $line;
+
+ $counter = $counter + 1;
+ }
+}
+
+close(FILE);
+
+if ($counter == 0) {
+ print "No matching code found \n";
+ exit;
+}
+
+if ($center == 0) {
+ print "No matching code found \n";
+ exit;
+}
+
+my $start;
+my $finish;
+my $codelines;
+my $binarylines;
+# now we go up and down in the array to find how much we want to print
+
+$start = $center;
+$codelines = 0;
+$binarylines = 0;
+while ($start > 1) {
+ $start = $start - 1;
+ my $line = $lines[$start];
+ if ($line =~ /^([a-f0-9]+)\:/) {
+ $binarylines = $binarylines + 1;
+ } else {
+ $codelines = $codelines + 1;
+ }
+ if ($codelines > 10) {
+ last;
+ }
+ if ($binarylines > 20) {
+ last;
+ }
+}
+
+
+$finish = $center;
+$codelines = 0;
+$binarylines = 0;
+while ($finish < $counter) {
+ $finish = $finish + 1;
+ my $line = $lines[$finish];
+ if ($line =~ /^([a-f0-9]+)\:/) {
+ $binarylines = $binarylines + 1;
+ } else {
+ $codelines = $codelines + 1;
+ }
+ if ($codelines > 10) {
+ last;
+ }
+ if ($binarylines > 20) {
+ last;
+ }
+}
+
+
+my $i;
+
+my $fulltext = "";
+$i = $start;
+while ($i < $finish) {
+ if ($i == $center) {
+ $fulltext = $fulltext . "*$lines[$i] <----- faulting instruction\n";
+ } else {
+ $fulltext = $fulltext . " $lines[$i]\n";
+ }
+ $i = $i +1;
+}
+
+
+
+print $fulltext;
+
--
1.6.0.3


--
Arjan van de Ven Intel Open Source Technology Centre
For development, discussion and tips for power savings,
visit http://www.lesswatts.org


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