diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/BUG-HUNTING | 113 | ||||
| -rw-r--r-- | Documentation/dvb/get_dvb_firmware | 2 | ||||
| -rw-r--r-- | Documentation/filesystems/isofs.txt | 4 | ||||
| -rw-r--r-- | Documentation/filesystems/jfs.txt | 2 | ||||
| -rw-r--r-- | Documentation/filesystems/vfat.txt | 6 | ||||
| -rw-r--r-- | Documentation/spinlocks.txt | 2 |
6 files changed, 121 insertions, 8 deletions
diff --git a/Documentation/BUG-HUNTING b/Documentation/BUG-HUNTING index ca29242dbc3..65b97e1dbf7 100644 --- a/Documentation/BUG-HUNTING +++ b/Documentation/BUG-HUNTING @@ -1,3 +1,56 @@ +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. @@ -90,3 +143,63 @@ it does work and it lets non-hackers help fix bugs. And it is cool 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. diff --git a/Documentation/dvb/get_dvb_firmware b/Documentation/dvb/get_dvb_firmware index bb55f49f274..15fc8fbef67 100644 --- a/Documentation/dvb/get_dvb_firmware +++ b/Documentation/dvb/get_dvb_firmware @@ -246,7 +246,7 @@ sub vp7041 { } 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"; diff --git a/Documentation/filesystems/isofs.txt b/Documentation/filesystems/isofs.txt index 424585ff6ea..758e50401c1 100644 --- a/Documentation/filesystems/isofs.txt +++ b/Documentation/filesystems/isofs.txt @@ -9,9 +9,9 @@ when using discs encoded using Microsoft's Joliet extensions. 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 diff --git a/Documentation/filesystems/jfs.txt b/Documentation/filesystems/jfs.txt index 3e992daf99a..bae12866374 100644 --- a/Documentation/filesystems/jfs.txt +++ b/Documentation/filesystems/jfs.txt @@ -6,7 +6,7 @@ The following mount options are supported: 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. diff --git a/Documentation/filesystems/vfat.txt b/Documentation/filesystems/vfat.txt index 5ead20c6c74..2001abbc60e 100644 --- a/Documentation/filesystems/vfat.txt +++ b/Documentation/filesystems/vfat.txt @@ -28,16 +28,16 @@ iocharset=name -- Character set to use for converting between the know how to deal with Unicode. By default, FAT_DEFAULT_IOCHARSET setting is used. - There is also an option of doing UTF8 translations + There is also an option of doing UTF-8 translations with the utf8 option. NOTE: "iocharset=utf8" is not recommended. If unsure, you should consider the following option instead. -utf8=<bool> -- UTF8 is the filesystem safe version of Unicode that +utf8=<bool> -- UTF-8 is the filesystem safe version of Unicode that is used by the console. It can be be enabled for the filesystem with this option. If 'uni_xlate' gets set, - UTF8 gets disabled. + UTF-8 gets disabled. uni_xlate=<bool> -- Translate unhandled Unicode characters to special escaped sequences. This would let you backup and diff --git a/Documentation/spinlocks.txt b/Documentation/spinlocks.txt index c2122996631..a661d684768 100644 --- a/Documentation/spinlocks.txt +++ b/Documentation/spinlocks.txt @@ -9,7 +9,7 @@ removed soon. So for any new code dynamic initialization should be used: static int __init xxx_init(void) { spin_lock_init(&xxx_lock); - rw_lock_init(&xxx_rw_lock); + rwlock_init(&xxx_rw_lock); ... } |