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Commit 5aea50b5 authored by Arjan van de Ven's avatar Arjan van de Ven Committed by Linus Torvalds
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scripts: script from kerneloops.org to pretty print oops dumps 



We're struggling 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_oops.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.
* It only works on x86

Signed-off-by: default avatarArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d6624f99

scripts/markup_oops.pl

0 → 100644
+162 −0
Original line number Diff line number Diff line 
#!/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 = 0;

my $binarylines = 0;

# now we go up and down in the array to find how much we want to print



$start = $center;



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;