Merge git://git.kernel.org/pub/scm/linux/kernel/git/bunk/trivial

#

# Top-level generic files

#

tags

vmlinux*

System.map

Module.symvers

Table of contents

=================

Last updated: 20 December 2005

Contents

========

- Introduction

- Devices not appearing

- Finding patch that caused a bug

-- Finding using git-bisect

-- Finding it the old way

- Fixing the bug

Introduction

============

Always try the latest kernel from kernel.org and build from source. If you are

not confident in doing that please report the bug to your distribution vendor

instead of to a kernel developer.

Finding bugs is not always easy. Have a go though. If you can't find it don't

give up. Report as much as you have found to the relevant maintainer. See

MAINTAINERS for who that is for the subsystem you have worked on.

Before you submit a bug report read REPORTING-BUGS.

Devices not appearing

=====================

Often this is caused by udev. Check that first before blaming it on the

kernel.

Finding patch that caused a bug

===============================

Finding using git-bisect

------------------------

Using the provided tools with git makes finding bugs easy provided the bug is

reproducible.

Steps to do it:

- start using git for the kernel source

- read the man page for git-bisect

- have fun

Finding it the old way

----------------------

[Sat Mar  2 10:32:33 PST 1996 KERNEL_BUG-HOWTO lm@sgi.com (Larry McVoy)]

This is how to track down a bug if you know nothing about kernel hacking.  

because Linux snapshots will let you do this - something that you can't

do with vendor supplied releases.

Fixing the bug

==============

Nobody is going to tell you how to fix bugs. Seriously. You need to work it

out. But below are some hints on how to use the tools.

To debug a kernel, use objdump and look for the hex offset from the crash

output to find the valid line of code/assembler. Without debug symbols, you

will see the assembler code for the routine shown, but if your kernel has

debug symbols the C code will also be available. (Debug symbols can be enabled

in the kernel hacking menu of the menu configuration.) For example:

    objdump -r -S -l --disassemble net/dccp/ipv4.o

NB.: you need to be at the top level of the kernel tree for this to pick up

your C files.

If you don't have access to the code you can also debug on some crash dumps

e.g. crash dump output as shown by Dave Miller.

>    EIP is at ip_queue_xmit+0x14/0x4c0

>     ...

>    Code: 44 24 04 e8 6f 05 00 00 e9 e8 fe ff ff 8d 76 00 8d bc 27 00 00

>    00 00 55 57  56 53 81 ec bc 00 00 00 8b ac 24 d0 00 00 00 8b 5d 08

>    <8b> 83 3c 01 00 00 89 44  24 14 8b 45 28 85 c0 89 44 24 18 0f 85

>

>    Put the bytes into a "foo.s" file like this:

>

>           .text

>           .globl foo

>    foo:

>           .byte  .... /* bytes from Code: part of OOPS dump */

>

>    Compile it with "gcc -c -o foo.o foo.s" then look at the output of

>    "objdump --disassemble foo.o".

>

>    Output:

>

>    ip_queue_xmit:

>        push       %ebp

>        push       %edi

>        push       %esi

>        push       %ebx

>        sub        $0xbc, %esp

>        mov        0xd0(%esp), %ebp        ! %ebp = arg0 (skb)

>        mov        0x8(%ebp), %ebx         ! %ebx = skb->sk

>        mov        0x13c(%ebx), %eax       ! %eax = inet_sk(sk)->opt

Another very useful option of the Kernel Hacking section in menuconfig is

Debug memory allocations. This will help you see whether data has been

initialised and not set before use etc. To see the values that get assigned

with this look at mm/slab.c and search for POISON_INUSE. When using this an

Oops will often show the poisoned data instead of zero which is the default.

Once you have worked out a fix please submit it upstream. After all open

source is about sharing what you do and don't you want to be recognised for

your genius?

Please do read Documentation/SubmittingPatches though to help your code get

accepted.

}

sub dibusb {

	my $url = "http://www.linuxtv.org/downloads/firmware/dvb-dibusb-5.0.0.11.fw";

	my $url = "http://www.linuxtv.org/downloads/firmware/dvb-usb-dibusb-5.0.0.11.fw";

	my $outfile = "dvb-dibusb-5.0.0.11.fw";

	my $hash = "fa490295a527360ca16dcdf3224ca243";

  iocharset=name Character set to use for converting from Unicode to

		ASCII.  Joliet filenames are stored in Unicode format, but

		Unix for the most part doesn't know how to deal with Unicode.

		There is also an option of doing UTF8 translations with the

		There is also an option of doing UTF-8 translations with the

		utf8 option.

  utf8          Encode Unicode names in UTF8 format. Default is no.

  utf8          Encode Unicode names in UTF-8 format. Default is no.

Mount options unique to the isofs filesystem.

  block=512     Set the block size for the disk to 512 bytes

iocharset=name	Character set to use for converting from Unicode to

		ASCII.  The default is to do no conversion.  Use

		iocharset=utf8 for UTF8 translations.  This requires

		iocharset=utf8 for UTF-8 translations.  This requires

		CONFIG_NLS_UTF8 to be set in the kernel .config file.

		iocharset=none specifies the default behavior explicitly.