From 9d85025b0418163fae079c9ba8f8445212de8568 Mon Sep 17 00:00:00 2001 From: Mauro Carvalho Chehab Date: Wed, 21 Sep 2016 09:51:11 -0300 Subject: docs-rst: create an user's manual book Place README, REPORTING-BUGS, SecurityBugs and kernel-parameters on an user's manual book. As we'll be numbering the user's manual, remove the manual numbering from SecurityBugs. Signed-off-by: Mauro Carvalho Chehab --- Documentation/BUG-HUNTING | 248 -- Documentation/SecurityBugs | 46 - Documentation/VGA-softcursor.txt | 66 - Documentation/admin-guide/README.rst | 410 ++ Documentation/admin-guide/bad-memory.rst | 50 + Documentation/admin-guide/basic-profiling.rst | 68 + Documentation/admin-guide/binfmt-misc.rst | 151 + Documentation/admin-guide/braille-console.rst | 38 + Documentation/admin-guide/bug-hunting.rst | 248 ++ Documentation/admin-guide/conf.py | 10 + Documentation/admin-guide/devices.rst | 3350 +++++++++++++++ Documentation/admin-guide/dynamic-debug-howto.rst | 353 ++ Documentation/admin-guide/index.rst | 34 + Documentation/admin-guide/init.rst | 52 + Documentation/admin-guide/initrd.rst | 383 ++ Documentation/admin-guide/java.rst | 417 ++ Documentation/admin-guide/kernel-parameters.rst | 4577 +++++++++++++++++++++ Documentation/admin-guide/md.rst | 727 ++++ Documentation/admin-guide/mono.rst | 68 + Documentation/admin-guide/oops-tracing.rst | 300 ++ Documentation/admin-guide/parport.rst | 286 ++ Documentation/admin-guide/ramoops.rst | 154 + Documentation/admin-guide/reporting-bugs.rst | 182 + Documentation/admin-guide/security-bugs.rst | 46 + Documentation/admin-guide/serial-console.rst | 115 + Documentation/admin-guide/sysfs-rules.rst | 192 + Documentation/admin-guide/sysrq.rst | 289 ++ Documentation/admin-guide/unicode.rst | 189 + Documentation/admin-guide/vga-softcursor.rst | 66 + Documentation/bad_memory.txt | 51 - Documentation/basic_profiling.txt | 69 - Documentation/binfmt_misc.txt | 151 - Documentation/braille-console.txt | 38 - Documentation/conf.py | 2 + Documentation/devices.txt | 3351 --------------- Documentation/dynamic-debug-howto.txt | 353 -- Documentation/index.rst | 1 + Documentation/init.txt | 52 - Documentation/initrd.txt | 383 -- Documentation/java.txt | 418 -- Documentation/kernel-parameters.txt | 4577 --------------------- Documentation/md.txt | 727 ---- Documentation/mono.txt | 68 - Documentation/oops-tracing.txt | 300 -- Documentation/parport.txt | 286 -- Documentation/ramoops.txt | 154 - Documentation/serial-console.txt | 115 - Documentation/sysfs-rules.txt | 192 - Documentation/sysrq.txt | 289 -- Documentation/unicode.txt | 189 - README | 411 -- REPORTING-BUGS | 182 - 52 files changed, 12758 insertions(+), 12716 deletions(-) delete mode 100644 Documentation/BUG-HUNTING delete mode 100644 Documentation/SecurityBugs delete mode 100644 Documentation/VGA-softcursor.txt create mode 100644 Documentation/admin-guide/README.rst create mode 100644 Documentation/admin-guide/bad-memory.rst create mode 100644 Documentation/admin-guide/basic-profiling.rst create mode 100644 Documentation/admin-guide/binfmt-misc.rst create mode 100644 Documentation/admin-guide/braille-console.rst create mode 100644 Documentation/admin-guide/bug-hunting.rst create mode 100644 Documentation/admin-guide/conf.py create mode 100644 Documentation/admin-guide/devices.rst create mode 100644 Documentation/admin-guide/dynamic-debug-howto.rst create mode 100644 Documentation/admin-guide/index.rst create mode 100644 Documentation/admin-guide/init.rst create mode 100644 Documentation/admin-guide/initrd.rst create mode 100644 Documentation/admin-guide/java.rst create mode 100644 Documentation/admin-guide/kernel-parameters.rst create mode 100644 Documentation/admin-guide/md.rst create mode 100644 Documentation/admin-guide/mono.rst create mode 100644 Documentation/admin-guide/oops-tracing.rst create mode 100644 Documentation/admin-guide/parport.rst create mode 100644 Documentation/admin-guide/ramoops.rst create mode 100644 Documentation/admin-guide/reporting-bugs.rst create mode 100644 Documentation/admin-guide/security-bugs.rst create mode 100644 Documentation/admin-guide/serial-console.rst create mode 100644 Documentation/admin-guide/sysfs-rules.rst create mode 100644 Documentation/admin-guide/sysrq.rst create mode 100644 Documentation/admin-guide/unicode.rst create mode 100644 Documentation/admin-guide/vga-softcursor.rst delete mode 100644 Documentation/bad_memory.txt delete mode 100644 Documentation/basic_profiling.txt delete mode 100644 Documentation/binfmt_misc.txt delete mode 100644 Documentation/braille-console.txt delete mode 100644 Documentation/devices.txt delete mode 100644 Documentation/dynamic-debug-howto.txt delete mode 100644 Documentation/init.txt delete mode 100644 Documentation/initrd.txt delete mode 100644 Documentation/java.txt delete mode 100644 Documentation/kernel-parameters.txt delete mode 100644 Documentation/md.txt delete mode 100644 Documentation/mono.txt delete mode 100644 Documentation/oops-tracing.txt delete mode 100644 Documentation/parport.txt delete mode 100644 Documentation/ramoops.txt delete mode 100644 Documentation/serial-console.txt delete mode 100644 Documentation/sysfs-rules.txt delete mode 100644 Documentation/sysrq.txt delete mode 100644 Documentation/unicode.txt delete mode 100644 README delete mode 100644 REPORTING-BUGS diff --git a/Documentation/BUG-HUNTING b/Documentation/BUG-HUNTING deleted file mode 100644 index a8ef794aadae..000000000000 --- a/Documentation/BUG-HUNTING +++ /dev/null @@ -1,248 +0,0 @@ -Bug hunting -+++++++++++ - -Last updated: 20 December 2005 - -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 -:ref:`Documentation/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. -It's a brute force approach but it works pretty well. - -You need: - - - A reproducible bug - it has to happen predictably (sorry) - - All the kernel tar files from a revision that worked to the - revision that doesn't - -You will then do: - - - Rebuild a revision that you believe works, install, and verify that. - - Do a binary search over the kernels to figure out which one - introduced the bug. I.e., suppose 1.3.28 didn't have the bug, but - you know that 1.3.69 does. Pick a kernel in the middle and build - that, like 1.3.50. Build & test; if it works, pick the mid point - between .50 and .69, else the mid point between .28 and .50. - - You'll narrow it down to the kernel that introduced the bug. You - can probably do better than this but it gets tricky. - - - Narrow it down to a subdirectory - - - Copy kernel that works into "test". Let's say that 3.62 works, - but 3.63 doesn't. So you diff -r those two kernels and come - up with a list of directories that changed. For each of those - directories: - - Copy the non-working directory next to the working directory - as "dir.63". - One directory at time, try moving the working directory to - "dir.62" and mv dir.63 dir"time, try:: - - mv dir dir.62 - mv dir.63 dir - find dir -name '*.[oa]' -print | xargs rm -f - - And then rebuild and retest. Assuming that all related - changes were contained in the sub directory, this should - isolate the change to a directory. - - Problems: changes in header files may have occurred; I've - found in my case that they were self explanatory - you may - or may not want to give up when that happens. - - - Narrow it down to a file - - - You can apply the same technique to each file in the directory, - hoping that the changes in that file are self contained. - - - Narrow it down to a routine - - - You can take the old file and the new file and manually create - a merged file that has:: - - #ifdef VER62 - routine() - { - ... - } - #else - routine() - { - ... - } - #endif - - And then walk through that file, one routine at a time and - prefix it with:: - - #define VER62 - /* both routines here */ - #undef VER62 - - Then recompile, retest, move the ifdefs until you find the one - that makes the difference. - -Finally, you take all the info that you have, kernel revisions, bug -description, the extent to which you have narrowed it down, and pass -that off to whomever you believe is the maintainer of that section. -A post to linux.dev.kernel isn't such a bad idea if you've done some -work to narrow it down. - -If you get it down to a routine, you'll probably get a fix in 24 hours. - -My apologies to Linus and the other kernel hackers for describing this -brute force approach, it's hardly what a kernel hacker would do. However, -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 - -.. note:: - - 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 - -In addition, you can use GDB to figure out the exact file and line -number of the OOPS from the ``vmlinux`` file. If you have -``CONFIG_DEBUG_INFO`` enabled, you can simply copy the EIP value from the -OOPS:: - - EIP: 0060:[] Not tainted VLI - -And use GDB to translate that to human-readable form:: - - gdb vmlinux - (gdb) l *0xc021e50e - -If you don't have ``CONFIG_DEBUG_INFO`` enabled, you use the function -offset from the OOPS:: - - EIP is at vt_ioctl+0xda8/0x1482 - -And recompile the kernel with ``CONFIG_DEBUG_INFO`` enabled:: - - make vmlinux - gdb vmlinux - (gdb) p vt_ioctl - (gdb) l *(0x
+ 0xda8) - -or, as one command:: - - (gdb) l *(vt_ioctl + 0xda8) - -If you have a call trace, such as:: - - Call Trace: - [] :jbd:log_wait_commit+0xa3/0xf5 - [] autoremove_wake_function+0x0/0x2e - [] :jbd:journal_stop+0x1be/0x1ee - ... - -this shows the problem in the :jbd: module. You can load that module in gdb -and list the relevant code:: - - gdb fs/jbd/jbd.ko - (gdb) p log_wait_commit - (gdb) l *(0x
+ 0xa3) - -or:: - - (gdb) l *(log_wait_commit + 0xa3) - - -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 :ref:`Documentation/SubmittingPatches ` -though to help your code get accepted. diff --git a/Documentation/SecurityBugs b/Documentation/SecurityBugs deleted file mode 100644 index 342d769834f6..000000000000 --- a/Documentation/SecurityBugs +++ /dev/null @@ -1,46 +0,0 @@ -.. _securitybugs: - -Security bugs -============= - -Linux kernel developers take security very seriously. As such, we'd -like to know when a security bug is found so that it can be fixed and -disclosed as quickly as possible. Please report security bugs to the -Linux kernel security team. - -1) Contact ----------- - -The Linux kernel security team can be contacted by email at -. This is a private list of security officers -who will help verify the bug report and develop and release a fix. -It is possible that the security team will bring in extra help from -area maintainers to understand and fix the security vulnerability. - -As it is with any bug, the more information provided the easier it -will be to diagnose and fix. Please review the procedure outlined in -REPORTING-BUGS if you are unclear about what information is helpful. -Any exploit code is very helpful and will not be released without -consent from the reporter unless it has already been made public. - -2) Disclosure -------------- - -The goal of the Linux kernel security team is to work with the -bug submitter to bug resolution as well as disclosure. We prefer -to fully disclose the bug as soon as possible. It is reasonable to -delay disclosure when the bug or the fix is not yet fully understood, -the solution is not well-tested or for vendor coordination. However, we -expect these delays to be short, measurable in days, not weeks or months. -A disclosure date is negotiated by the security team working with the -bug submitter as well as vendors. However, the kernel security team -holds the final say when setting a disclosure date. The timeframe for -disclosure is from immediate (esp. if it's already publicly known) -to a few weeks. As a basic default policy, we expect report date to -disclosure date to be on the order of 7 days. - -3) Non-disclosure agreements ----------------------------- - -The Linux kernel security team is not a formal body and therefore unable -to enter any non-disclosure agreements. diff --git a/Documentation/VGA-softcursor.txt b/Documentation/VGA-softcursor.txt deleted file mode 100644 index 9eac6744b3a1..000000000000 --- a/Documentation/VGA-softcursor.txt +++ /dev/null @@ -1,66 +0,0 @@ -Software cursor for VGA -======================= - -by Pavel Machek -and Martin Mares - -Linux now has some ability to manipulate cursor appearance. Normally, you -can set the size of hardware cursor (and also work around some ugly bugs in -those miserable Trident cards [#f1]_. You can now play a few new tricks: -you can make your cursor look - -like a non-blinking red block, make it inverse background of the character it's -over or to highlight that character and still choose whether the original -hardware cursor should remain visible or not. There may be other things I have -never thought of. - -The cursor appearance is controlled by a ``[?1;2;3c`` escape sequence -where 1, 2 and 3 are parameters described below. If you omit any of them, -they will default to zeroes. - -first Parameter - specifies cursor size:: - - 0=default - 1=invisible - 2=underline, - ... - 8=full block - + 16 if you want the software cursor to be applied - + 32 if you want to always change the background color - + 64 if you dislike having the background the same as the - foreground. - - Highlights are ignored for the last two flags. - -second parameter - selects character attribute bits you want to change - (by simply XORing them with the value of this parameter). On standard - VGA, the high four bits specify background and the low four the - foreground. In both groups, low three bits set color (as in normal - color codes used by the console) and the most significant one turns - on highlight (or sometimes blinking -- it depends on the configuration - of your VGA). - -third parameter - consists of character attribute bits you want to set. - - Bit setting takes place before bit toggling, so you can simply clear a - bit by including it in both the set mask and the toggle mask. - -.. [#f1] see ``#define TRIDENT_GLITCH`` in ``drivers/video/vgacon.c``. - -Examples: -========= - -To get normal blinking underline, use:: - - echo -e '\033[?2c' - -To get blinking block, use:: - - echo -e '\033[?6c' - -To get red non-blinking block, use:: - - echo -e '\033[?17;0;64c' diff --git a/Documentation/admin-guide/README.rst b/Documentation/admin-guide/README.rst new file mode 100644 index 000000000000..05aad8543340 --- /dev/null +++ b/Documentation/admin-guide/README.rst @@ -0,0 +1,410 @@ +Linux kernel release 4.x +============================================= + +These are the release notes for Linux version 4. Read them carefully, +as they tell you what this is all about, explain how to install the +kernel, and what to do if something goes wrong. + +What is Linux? +-------------- + + Linux is a clone of the operating system Unix, written from scratch by + Linus Torvalds with assistance from a loosely-knit team of hackers across + the Net. It aims towards POSIX and Single UNIX Specification compliance. + + It has all the features you would expect in a modern fully-fledged Unix, + including true multitasking, virtual memory, shared libraries, demand + loading, shared copy-on-write executables, proper memory management, + and multistack networking including IPv4 and IPv6. + + It is distributed under the GNU General Public License - see the + accompanying COPYING file for more details. + +On what hardware does it run? +----------------------------- + + Although originally developed first for 32-bit x86-based PCs (386 or higher), + today Linux also runs on (at least) the Compaq Alpha AXP, Sun SPARC and + UltraSPARC, Motorola 68000, PowerPC, PowerPC64, ARM, Hitachi SuperH, Cell, + IBM S/390, MIPS, HP PA-RISC, Intel IA-64, DEC VAX, AMD x86-64, AXIS CRIS, + Xtensa, Tilera TILE, AVR32, ARC and Renesas M32R architectures. + + Linux is easily portable to most general-purpose 32- or 64-bit architectures + as long as they have a paged memory management unit (PMMU) and a port of the + GNU C compiler (gcc) (part of The GNU Compiler Collection, GCC). Linux has + also been ported to a number of architectures without a PMMU, although + functionality is then obviously somewhat limited. + Linux has also been ported to itself. You can now run the kernel as a + userspace application - this is called UserMode Linux (UML). + +Documentation +------------- + + - There is a lot of documentation available both in electronic form on + the Internet and in books, both Linux-specific and pertaining to + general UNIX questions. I'd recommend looking into the documentation + subdirectories on any Linux FTP site for the LDP (Linux Documentation + Project) books. This README is not meant to be documentation on the + system: there are much better sources available. + + - There are various README files in the Documentation/ subdirectory: + these typically contain kernel-specific installation notes for some + drivers for example. See Documentation/00-INDEX for a list of what + is contained in each file. Please read the Changes file, as it + contains information about the problems, which may result by upgrading + your kernel. + + - The Documentation/DocBook/ subdirectory contains several guides for + kernel developers and users. These guides can be rendered in a + number of formats: PostScript (.ps), PDF, HTML, & man-pages, among others. + After installation, ``make psdocs``, ``make pdfdocs``, ``make htmldocs``, + or ``make mandocs`` will render the documentation in the requested format. + +Installing the kernel source +---------------------------- + + - If you install the full sources, put the kernel tarball in a + directory where you have permissions (e.g. your home directory) and + unpack it:: + + xz -cd linux-4.X.tar.xz | tar xvf - + + Replace "X" with the version number of the latest kernel. + + Do NOT use the /usr/src/linux area! This area has a (usually + incomplete) set of kernel headers that are used by the library header + files. They should match the library, and not get messed up by + whatever the kernel-du-jour happens to be. + + - You can also upgrade between 4.x releases by patching. Patches are + distributed in the xz format. To install by patching, get all the + newer patch files, enter the top level directory of the kernel source + (linux-4.X) and execute:: + + xz -cd ../patch-4.x.xz | patch -p1 + + Replace "x" for all versions bigger than the version "X" of your current + source tree, **in_order**, and you should be ok. You may want to remove + the backup files (some-file-name~ or some-file-name.orig), and make sure + that there are no failed patches (some-file-name# or some-file-name.rej). + If there are, either you or I have made a mistake. + + Unlike patches for the 4.x kernels, patches for the 4.x.y kernels + (also known as the -stable kernels) are not incremental but instead apply + directly to the base 4.x kernel. For example, if your base kernel is 4.0 + and you want to apply the 4.0.3 patch, you must not first apply the 4.0.1 + and 4.0.2 patches. Similarly, if you are running kernel version 4.0.2 and + want to jump to 4.0.3, you must first reverse the 4.0.2 patch (that is, + patch -R) **before** applying the 4.0.3 patch. You can read more on this in + :ref:`Documentation/applying-patches.txt `. + + Alternatively, the script patch-kernel can be used to automate this + process. It determines the current kernel version and applies any + patches found:: + + linux/scripts/patch-kernel linux + + The first argument in the command above is the location of the + kernel source. Patches are applied from the current directory, but + an alternative directory can be specified as the second argument. + + - Make sure you have no stale .o files and dependencies lying around:: + + cd linux + make mrproper + + You should now have the sources correctly installed. + +Software requirements +--------------------- + + Compiling and running the 4.x kernels requires up-to-date + versions of various software packages. Consult + :ref:`Documentation/Changes ` for the minimum version numbers + required and how to get updates for these packages. Beware that using + excessively old versions of these packages can cause indirect + errors that are very difficult to track down, so don't assume that + you can just update packages when obvious problems arise during + build or operation. + +Build directory for the kernel +------------------------------ + + When compiling the kernel, all output files will per default be + stored together with the kernel source code. + Using the option ``make O=output/dir`` allows you to specify an alternate + place for the output files (including .config). + Example:: + + kernel source code: /usr/src/linux-4.X + build directory: /home/name/build/kernel + + To configure and build the kernel, use:: + + cd /usr/src/linux-4.X + make O=/home/name/build/kernel menuconfig + make O=/home/name/build/kernel + sudo make O=/home/name/build/kernel modules_install install + + Please note: If the ``O=output/dir`` option is used, then it must be + used for all invocations of make. + +Configuring the kernel +---------------------- + + Do not skip this step even if you are only upgrading one minor + version. New configuration options are added in each release, and + odd problems will turn up if the configuration files are not set up + as expected. If you want to carry your existing configuration to a + new version with minimal work, use ``make oldconfig``, which will + only ask you for the answers to new questions. + + - Alternative configuration commands are:: + + "make config" Plain text interface. + + "make menuconfig" Text based color menus, radiolists & dialogs. + + "make nconfig" Enhanced text based color menus. + + "make xconfig" Qt based configuration tool. + + "make gconfig" GTK+ based configuration tool. + + "make oldconfig" Default all questions based on the contents of + your existing ./.config file and asking about + new config symbols. + + "make silentoldconfig" + Like above, but avoids cluttering the screen + with questions already answered. + Additionally updates the dependencies. + + "make olddefconfig" + Like above, but sets new symbols to their default + values without prompting. + + "make defconfig" Create a ./.config file by using the default + symbol values from either arch/$ARCH/defconfig + or arch/$ARCH/configs/${PLATFORM}_defconfig, + depending on the architecture. + + "make ${PLATFORM}_defconfig" + Create a ./.config file by using the default + symbol values from + arch/$ARCH/configs/${PLATFORM}_defconfig. + Use "make help" to get a list of all available + platforms of your architecture. + + "make allyesconfig" + Create a ./.config file by setting symbol + values to 'y' as much as possible. + + "make allmodconfig" + Create a ./.config file by setting symbol + values to 'm' as much as possible. + + "make allnoconfig" Create a ./.config file by setting symbol + values to 'n' as much as possible. + + "make randconfig" Create a ./.config file by setting symbol + values to random values. + + "make localmodconfig" Create a config based on current config and + loaded modules (lsmod). Disables any module + option that is not needed for the loaded modules. + + To create a localmodconfig for another machine, + store the lsmod of that machine into a file + and pass it in as a LSMOD parameter. + + target$ lsmod > /tmp/mylsmod + target$ scp /tmp/mylsmod host:/tmp + + host$ make LSMOD=/tmp/mylsmod localmodconfig + + The above also works when cross compiling. + + "make localyesconfig" Similar to localmodconfig, except it will convert + all module options to built in (=y) options. + + You can find more information on using the Linux kernel config tools + in Documentation/kbuild/kconfig.txt. + + - NOTES on ``make config``: + + - Having unnecessary drivers will make the kernel bigger, and can + under some circumstances lead to problems: probing for a + nonexistent controller card may confuse your other controllers + + - A kernel with math-emulation compiled in will still use the + coprocessor if one is present: the math emulation will just + never get used in that case. The kernel will be slightly larger, + but will work on different machines regardless of whether they + have a math coprocessor or not. + + - The "kernel hacking" configuration details usually result in a + bigger or slower kernel (or both), and can even make the kernel + less stable by configuring some routines to actively try to + break bad code to find kernel problems (kmalloc()). Thus you + should probably answer 'n' to the questions for "development", + "experimental", or "debugging" features. + +Compiling the kernel +-------------------- + + - Make sure you have at least gcc 3.2 available. + For more information, refer to :ref:`Documentation/Changes `. + + Please note that you can still run a.out user programs with this kernel. + + - Do a ``make`` to create a compressed kernel image. It is also + possible to do ``make install`` if you have lilo installed to suit the + kernel makefiles, but you may want to check your particular lilo setup first. + + To do the actual install, you have to be root, but none of the normal + build should require that. Don't take the name of root in vain. + + - If you configured any of the parts of the kernel as ``modules``, you + will also have to do ``make modules_install``. + + - Verbose kernel compile/build output: + + Normally, the kernel build system runs in a fairly quiet mode (but not + totally silent). However, sometimes you or other kernel developers need + to see compile, link, or other commands exactly as they are executed. + For this, use "verbose" build mode. This is done by passing + ``V=1`` to the ``make`` command, e.g.:: + + make V=1 all + + To have the build system also tell the reason for the rebuild of each + target, use ``V=2``. The default is ``V=0``. + + - Keep a backup kernel handy in case something goes wrong. This is + especially true for the development releases, since each new release + contains new code which has not been debugged. Make sure you keep a + backup of the modules corresponding to that kernel, as well. If you + are installing a new kernel with the same version number as your + working kernel, make a backup of your modules directory before you + do a ``make modules_install``. + + Alternatively, before compiling, use the kernel config option + "LOCALVERSION" to append a unique suffix to the regular kernel version. + LOCALVERSION can be set in the "General Setup" menu. + + - In order to boot your new kernel, you'll need to copy the kernel + image (e.g. .../linux/arch/x86/boot/bzImage after compilation) + to the place where your regular bootable kernel is found. + + - Booting a kernel directly from a floppy without the assistance of a + bootloader such as LILO, is no longer supported. + + If you boot Linux from the hard drive, chances are you use LILO, which + uses the kernel image as specified in the file /etc/lilo.conf. The + kernel image file is usually /vmlinuz, /boot/vmlinuz, /bzImage or + /boot/bzImage. To use the new kernel, save a copy of the old image + and copy the new image over the old one. Then, you MUST RERUN LILO + to update the loading map! If you don't, you won't be able to boot + the new kernel image. + + Reinstalling LILO is usually a matter of running /sbin/lilo. + You may wish to edit /etc/lilo.conf to specify an entry for your + old kernel image (say, /vmlinux.old) in case the new one does not + work. See the LILO docs for more information. + + After reinstalling LILO, you should be all set. Shutdown the system, + reboot, and enjoy! + + If you ever need to change the default root device, video mode, + ramdisk size, etc. in the kernel image, use the ``rdev`` program (or + alternatively the LILO boot options when appropriate). No need to + recompile the kernel to change these parameters. + + - Reboot with the new kernel and enjoy. + +If something goes wrong +----------------------- + + - If you have problems that seem to be due to kernel bugs, please check + the file MAINTAINERS to see if there is a particular person associated + with the part of the kernel that you are having trouble with. If there + isn't anyone listed there, then the second best thing is to mail + them to me (torvalds@linux-foundation.org), and possibly to any other + relevant mailing-list or to the newsgroup. + + - In all bug-reports, *please* tell what kernel you are talking about, + how to duplicate the problem, and what your setup is (use your common + sense). If the problem is new, tell me so, and if the problem is + old, please try to tell me when you first noticed it. + + - If the bug results in a message like:: + + unable to handle kernel paging request at address C0000010 + Oops: 0002 + EIP: 0010:XXXXXXXX + eax: xxxxxxxx ebx: xxxxxxxx ecx: xxxxxxxx edx: xxxxxxxx + esi: xxxxxxxx edi: xxxxxxxx ebp: xxxxxxxx + ds: xxxx es: xxxx fs: xxxx gs: xxxx + Pid: xx, process nr: xx + xx xx xx xx xx xx xx xx xx xx + + or similar kernel debugging information on your screen or in your + system log, please duplicate it *exactly*. The dump may look + incomprehensible to you, but it does contain information that may + help debugging the problem. The text above the dump is also + important: it tells something about why the kernel dumped code (in + the above example, it's due to a bad kernel pointer). More information + on making sense of the dump is in Documentation/oops-tracing.txt + + - If you compiled the kernel with CONFIG_KALLSYMS you can send the dump + as is, otherwise you will have to use the ``ksymoops`` program to make + sense of the dump (but compiling with CONFIG_KALLSYMS is usually preferred). + This utility can be downloaded from + ftp://ftp..kernel.org/pub/linux/utils/kernel/ksymoops/ . + Alternatively, you can do the dump lookup by hand: + + - In debugging dumps like the above, it helps enormously if you can + look up what the EIP value means. The hex value as such doesn't help + me or anybody else very much: it will depend on your particular + kernel setup. What you should do is take the hex value from the EIP + line (ignore the ``0010:``), and look it up in the kernel namelist to + see which kernel function contains the offending address. + + To find out the kernel function name, you'll need to find the system + binary associated with the kernel that exhibited the symptom. This is + the file 'linux/vmlinux'. To extract the namelist and match it against + the EIP from the kernel crash, do:: + + nm vmlinux | sort | less + + This will give you a list of kernel addresses sorted in ascending + order, from which it is simple to find the function that contains the + offending address. Note that the address given by the kernel + debugging messages will not necessarily match exactly with the + function addresses (in fact, that is very unlikely), so you can't + just 'grep' the list: the list will, however, give you the starting + point of each kernel function, so by looking for the function that + has a starting address lower than the one you are searching for but + is followed by a function with a higher address you will find the one + you want. In fact, it may be a good idea to include a bit of + "context" in your problem report, giving a few lines around the + interesting one. + + If you for some reason cannot do the above (you have a pre-compiled + kernel image or similar), telling me as much about your setup as + possible will help. Please read the :ref:`REPORTING-BUGS ` + document for details. + + - Alternatively, you can use gdb on a running kernel. (read-only; i.e. you + cannot change values or set break points.) To do this, first compile the + kernel with -g; edit arch/x86/Makefile appropriately, then do a ``make + clean``. You'll also need to enable CONFIG_PROC_FS (via ``make config``). + + After you've rebooted with the new kernel, do ``gdb vmlinux /proc/kcore``. + You can now use all the usual gdb commands. The command to look up the + point where your system crashed is ``l *0xXXXXXXXX``. (Replace the XXXes + with the EIP value.) + + gdb'ing a non-running kernel currently fails because ``gdb`` (wrongly) + disregards the starting offset for which the kernel is compiled. diff --git a/Documentation/admin-guide/bad-memory.rst b/Documentation/admin-guide/bad-memory.rst new file mode 100644 index 000000000000..017fc86430c3 --- /dev/null +++ b/Documentation/admin-guide/bad-memory.rst @@ -0,0 +1,50 @@ +How to deal with bad memory e.g. reported by memtest86+ ? +========================================================= + +March 2008 +Jan-Simon Moeller, dl9pf@gmx.de + + + +There are three possibilities I know of: + +1) Reinsert/swap the memory modules + +2) Buy new modules (best!) or try to exchange the memory + if you have spare-parts + +3) Use BadRAM or memmap + +This Howto is about number 3) . + + +BadRAM +###### + +BadRAM is the actively developed and available as kernel-patch +here: http://rick.vanrein.org/linux/badram/ + +For more details see the BadRAM documentation. + +memmap +###### + +memmap is already in the kernel and usable as kernel-parameter at +boot-time. Its syntax is slightly strange and you may need to +calculate the values by yourself! + +Syntax to exclude a memory area (see kernel-parameters.txt for details):: + + memmap=$
+ +Example: memtest86+ reported here errors at address 0x18691458, 0x18698424 and +some others. All had 0x1869xxxx in common, so I chose a pattern of +0x18690000,0xffff0000. + +With the numbers of the example above:: + + memmap=64K$0x18690000 + +or:: + + memmap=0x10000$0x18690000 diff --git a/Documentation/admin-guide/basic-profiling.rst b/Documentation/admin-guide/basic-profiling.rst new file mode 100644 index 000000000000..72babc71b771 --- /dev/null +++ b/Documentation/admin-guide/basic-profiling.rst @@ -0,0 +1,68 @@ +Basic kernel profiling +====================== + + +These instructions are deliberately very basic. If you want something clever, +go read the real docs ;-) + +Please don't add more stuff, but feel free to +correct my mistakes ;-) (mbligh@aracnet.com) + +Thanks to John Levon, Dave Hansen, et al. for help writing this. + +```` is the thing you're trying to measure. +Make sure you have the correct ``System.map`` / ``vmlinux`` referenced! + +It is probably easiest to use ``make install`` for linux and hack +``/sbin/installkernel`` to copy ``vmlinux`` to ``/boot``, in addition to +``vmlinuz``, ``config``, ``System.map``, which are usually installed by default. + +Readprofile +----------- + +A recent ``readprofile`` command is needed for 2.6, such as found in util-linux +2.12a, which can be downloaded from: + + http://www.kernel.org/pub/linux/utils/util-linux/ + +Most distributions will ship it already. + +Add ``profile=2`` to the kernel command line. + +Some ``readprofile`` commands:: + + clear readprofile -r + + dump output readprofile -m /boot/System.map > captured_profile + +Oprofile +-------- + +Get the source (see Changes for required version) from +http://oprofile.sourceforge.net/ and add ``idle=poll`` to the kernel command +line. + +Configure with ``CONFIG_PROFILING=y`` and ``CONFIG_OPROFILE=y`` & reboot on new kernel:: + + ./configure --with-kernel-support + make install + +For superior results, be sure to enable the local APIC. If opreport sees +a 0Hz CPU, APIC was not on. Be aware that idle=poll may mean a performance +penalty. + +One time setup:: + + opcontrol --setup --vmlinux=/boot/vmlinux + +Some ``opcontrol`` commands:: + + clear opcontrol --reset + start opcontrol --start + + stop opcontrol --stop + dump output opreport > output_file + +To only report on the kernel, run ``opreport -l /boot/vmlinux > output_file`` + +A reset is needed to clear old statistics, which survive a reboot. diff --git a/Documentation/admin-guide/binfmt-misc.rst b/Documentation/admin-guide/binfmt-misc.rst new file mode 100644 index 000000000000..9c5ff8f260bf --- /dev/null +++ b/Documentation/admin-guide/binfmt-misc.rst @@ -0,0 +1,151 @@ +Kernel Support for miscellaneous (your favourite) Binary Formats v1.1 +===================================================================== + +This Kernel feature allows you to invoke almost (for restrictions see below) +every program by simply typing its name in the shell. +This includes for example compiled Java(TM), Python or Emacs programs. + +To achieve this you must tell binfmt_misc which interpreter has to be invoked +with which binary. Binfmt_misc recognises the binary-type by matching some bytes +at the beginning of the file with a magic byte sequence (masking out specified +bits) you have supplied. Binfmt_misc can also recognise a filename extension +aka ``.com`` or ``.exe``. + +First you must mount binfmt_misc:: + + mount binfmt_misc -t binfmt_misc /proc/sys/fs/binfmt_misc + +To actually register a new binary type, you have to set up a string looking like +``:name:type:offset:magic:mask:interpreter:flags`` (where you can choose the +``:`` upon your needs) and echo it to ``/proc/sys/fs/binfmt_misc/register``. + +Here is what the fields mean: + +- ``name`` + is an identifier string. A new /proc file will be created with this + ``name below /proc/sys/fs/binfmt_misc``; cannot contain slashes ``/`` for + obvious reasons. +- ``type`` + is the type of recognition. Give ``M`` for magic and ``E`` for extension. +- ``offset`` + is the offset of the magic/mask in the file, counted in bytes. This + defaults to 0 if you omit it (i.e. you write ``:name:type::magic...``). + Ignored when using filename extension matching. +- ``magic`` + is the byte sequence binfmt_misc is matching for. The magic string + may contain hex-encoded characters like ``\x0a`` or ``\xA4``. Note that you + must escape any NUL bytes; parsing halts at the first one. In a shell + environment you might have to write ``\\x0a`` to prevent the shell from + eating your ``\``. + If you chose filename extension matching, this is the extension to be + recognised (without the ``.``, the ``\x0a`` specials are not allowed). + Extension matching is case sensitive, and slashes ``/`` are not allowed! +- ``mask`` + is an (optional, defaults to all 0xff) mask. You can mask out some + bits from matching by supplying a string like magic and as long as magic. + The mask is anded with the byte sequence of the file. Note that you must + escape any NUL bytes; parsing halts at the first one. Ignored when using + filename extension matching. +- ``interpreter`` + is the program that should be invoked with the binary as first + argument (specify the full path) +- ``flags`` + is an optional field that controls several aspects of the invocation + of the interpreter. It is a string of capital letters, each controls a + certain aspect. The following flags are supported: + + ``P`` - preserve-argv[0] + Legacy behavior of binfmt_misc is to overwrite + the original argv[0] with the full path to the binary. When this + flag is included, binfmt_misc will add an argument to the argument + vector for this purpose, thus preserving the original ``argv[0]``. + e.g. If your interp is set to ``/bin/foo`` and you run ``blah`` + (which is in ``/usr/local/bin``), then the kernel will execute + ``/bin/foo`` with ``argv[]`` set to ``["/bin/foo", "/usr/local/bin/blah", "blah"]``. The interp has to be aware of this so it can + execute ``/usr/local/bin/blah`` + with ``argv[]`` set to ``["blah"]``. + ``O`` - open-binary + Legacy behavior of binfmt_misc is to pass the full path + of the binary to the interpreter as an argument. When this flag is + included, binfmt_misc will open the file for reading and pass its + descriptor as an argument, instead of the full path, thus allowing + the interpreter to execute non-readable binaries. This feature + should be used with care - the interpreter has to be trusted not to + emit the contents of the non-readable binary. + ``C`` - credentials + Currently, the behavior of binfmt_misc is to calculate + the credentials and security token of the new process according to + the interpreter. When this flag is included, these attributes are + calculated according to the binary. It also implies the ``O`` flag. + This feature should be used with care as the interpreter + will run with root permissions when a setuid binary owned by root + is run with binfmt_misc. + ``F`` - fix binary + The usual behaviour of binfmt_misc is to spawn the + binary lazily when the misc format file is invoked. However, + this doesn``t work very well in the face of mount namespaces and + changeroots, so the ``F`` mode opens the binary as soon as the + emulation is installed and uses the opened image to spawn the + emulator, meaning it is always available once installed, + regardless of how the environment changes. + + +There are some restrictions: + + - the whole register string may not exceed 1920 characters + - the magic must reside in the first 128 bytes of the file, i.e. + offset+size(magic) has to be less than 128 + - the interpreter string may not exceed 127 characters + +To use binfmt_misc you have to mount it first. You can mount it with +``mount -t binfmt_misc none /proc/sys/fs/binfmt_misc`` command, or you can add +a line ``none /proc/sys/fs/binfmt_misc binfmt_misc defaults 0 0`` to your +``/etc/fstab`` so it auto mounts on boot. + +You may want to add the binary formats in one of your ``/etc/rc`` scripts during +boot-up. Read the manual of your init program to figure out how to do this +right. + +Think about the order of adding entries! Later added entries are matched first! + + +A few examples (assumed you are in ``/proc/sys/fs/binfmt_misc``): + +- enable support for em86 (like binfmt_em86, for Alpha AXP only):: + + echo ':i386:M::\x7fELF\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x03:\xff\xff\xff\xff\xff\xfe\xfe\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfb\xff\xff:/bin/em86:' > register + echo ':i486:M::\x7fELF\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\x06:\xff\xff\xff\xff\xff\xfe\xfe\xff\xff\xff\xff\xff\xff\xff\xff\xff\xfb\xff\xff:/bin/em86:' > register + +- enable support for packed DOS applications (pre-configured dosemu hdimages):: + + echo ':DEXE:M::\x0eDEX::/usr/bin/dosexec:' > register + +- enable support for Windows executables using wine:: + + echo ':DOSWin:M::MZ::/usr/local/bin/wine:' > register + +For java support see Documentation/java.txt + + +You can enable/disable binfmt_misc or one binary type by echoing 0 (to disable) +or 1 (to enable) to ``/proc/sys/fs/binfmt_misc/status`` or +``/proc/.../the_name``. +Catting the file tells you the current status of ``binfmt_misc/the_entry``. + +You can remove one entry or all entries by echoing -1 to ``/proc/.../the_name`` +or ``/proc/sys/fs/binfmt_misc/status``. + + +Hints +----- + +If you want to pass special arguments to your interpreter, you can +write a wrapper script for it. See Documentation/java.txt for an +example. + +Your interpreter should NOT look in the PATH for the filename; the kernel +passes it the full filename (or the file descriptor) to use. Using ``$PATH`` can +cause unexpected behaviour and can be a security hazard. + + +Richard Günther diff --git a/Documentation/admin-guide/braille-console.rst b/Documentation/admin-guide/braille-console.rst new file mode 100644 index 000000000000..fa3702dc04ab --- /dev/null +++ b/Documentation/admin-guide/braille-console.rst @@ -0,0 +1,38 @@ +Linux Braille Console +===================== + +To get early boot messages on a braille device (before userspace screen +readers can start), you first need to compile the support for the usual serial +console (see :ref:`Documentation/serial-console.txt `), and +for braille device +(in :menuselection:`Device Drivers --> Accessibility support --> Console on braille device`). + +Then you need to specify a ``console=brl``, option on the kernel command line, the +format is:: + + console=brl,serial_options... + +where ``serial_options...`` are the same as described in +:ref:`Documentation/serial-console.txt `. + +So for instance you can use ``console=brl,ttyS0`` if the braille device is connected to the first serial port, and ``console=brl,ttyS0,115200`` to +override the baud rate to 115200, etc. + +By default, the braille device will just show the last kernel message (console +mode). To review previous messages, press the Insert key to switch to the VT +review mode. In review mode, the arrow keys permit to browse in the VT content, +:kbd:`PAGE-UP`/:kbd:`PAGE-DOWN` keys go at the top/bottom of the screen, and +the :kbd:`HOME` key goes back +to the cursor, hence providing very basic screen reviewing facility. + +Sound feedback can be obtained by adding the ``braille_console.sound=1`` kernel +parameter. + +For simplicity, only one braille console can be enabled, other uses of +``console=brl,...`` will be discarded. Also note that it does not interfere with +the console selection mechanism described in +:ref:`Documentation/serial-console.txt `. + +For now, only the VisioBraille device is supported. + +Samuel Thibault diff --git a/Documentation/admin-guide/bug-hunting.rst b/Documentation/admin-guide/bug-hunting.rst new file mode 100644 index 000000000000..a8ef794aadae --- /dev/null +++ b/Documentation/admin-guide/bug-hunting.rst @@ -0,0 +1,248 @@ +Bug hunting ++++++++++++ + +Last updated: 20 December 2005 + +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 +:ref:`Documentation/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. +It's a brute force approach but it works pretty well. + +You need: + + - A reproducible bug - it has to happen predictably (sorry) + - All the kernel tar files from a revision that worked to the + revision that doesn't + +You will then do: + + - Rebuild a revision that you believe works, install, and verify that. + - Do a binary search over the kernels to figure out which one + introduced the bug. I.e., suppose 1.3.28 didn't have the bug, but + you know that 1.3.69 does. Pick a kernel in the middle and build + that, like 1.3.50. Build & test; if it works, pick the mid point + between .50 and .69, else the mid point between .28 and .50. + - You'll narrow it down to the kernel that introduced the bug. You + can probably do better than this but it gets tricky. + + - Narrow it down to a subdirectory + + - Copy kernel that works into "test". Let's say that 3.62 works, + but 3.63 doesn't. So you diff -r those two kernels and come + up with a list of directories that changed. For each of those + directories: + + Copy the non-working directory next to the working directory + as "dir.63". + One directory at time, try moving the working directory to + "dir.62" and mv dir.63 dir"time, try:: + + mv dir dir.62 + mv dir.63 dir + find dir -name '*.[oa]' -print | xargs rm -f + + And then rebuild and retest. Assuming that all related + changes were contained in the sub directory, this should + isolate the change to a directory. + + Problems: changes in header files may have occurred; I've + found in my case that they were self explanatory - you may + or may not want to give up when that happens. + + - Narrow it down to a file + + - You can apply the same technique to each file in the directory, + hoping that the changes in that file are self contained. + + - Narrow it down to a routine + + - You can take the old file and the new file and manually create + a merged file that has:: + + #ifdef VER62 + routine() + { + ... + } + #else + routine() + { + ... + } + #endif + + And then walk through that file, one routine at a time and + prefix it with:: + + #define VER62 + /* both routines here */ + #undef VER62 + + Then recompile, retest, move the ifdefs until you find the one + that makes the difference. + +Finally, you take all the info that you have, kernel revisions, bug +description, the extent to which you have narrowed it down, and pass +that off to whomever you believe is the maintainer of that section. +A post to linux.dev.kernel isn't such a bad idea if you've done some +work to narrow it down. + +If you get it down to a routine, you'll probably get a fix in 24 hours. + +My apologies to Linus and the other kernel hackers for describing this +brute force approach, it's hardly what a kernel hacker would do. However, +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 + +.. note:: + + 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 + +In addition, you can use GDB to figure out the exact file and line +number of the OOPS from the ``vmlinux`` file. If you have +``CONFIG_DEBUG_INFO`` enabled, you can simply copy the EIP value from the +OOPS:: + + EIP: 0060:[] Not tainted VLI + +And use GDB to translate that to human-readable form:: + + gdb vmlinux + (gdb) l *0xc021e50e + +If you don't have ``CONFIG_DEBUG_INFO`` enabled, you use the function +offset from the OOPS:: + + EIP is at vt_ioctl+0xda8/0x1482 + +And recompile the kernel with ``CONFIG_DEBUG_INFO`` enabled:: + + make vmlinux + gdb vmlinux + (gdb) p vt_ioctl + (gdb) l *(0x
+ 0xda8) + +or, as one command:: + + (gdb) l *(vt_ioctl + 0xda8) + +If you have a call trace, such as:: + + Call Trace: + [] :jbd:log_wait_commit+0xa3/0xf5 + [] autoremove_wake_function+0x0/0x2e + [] :jbd:journal_stop+0x1be/0x1ee + ... + +this shows the problem in the :jbd: module. You can load that module in gdb +and list the relevant code:: + + gdb fs/jbd/jbd.ko + (gdb) p log_wait_commit + (gdb) l *(0x
+ 0xa3) + +or:: + + (gdb) l *(log_wait_commit + 0xa3) + + +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 :ref:`Documentation/SubmittingPatches ` +though to help your code get accepted. diff --git a/Documentation/admin-guide/conf.py b/Documentation/admin-guide/conf.py new file mode 100644 index 000000000000..86f738953799 --- /dev/null +++ b/Documentation/admin-guide/conf.py @@ -0,0 +1,10 @@ +# -*- coding: utf-8; mode: python -*- + +project = 'Linux Kernel User Documentation' + +tags.add("subproject") + +latex_documents = [ + ('index', 'linux-user.tex', 'Linux Kernel User Documentation', + 'The kernel development community', 'manual'), +] diff --git a/Documentation/admin-guide/devices.rst b/Documentation/admin-guide/devices.rst new file mode 100644 index 000000000000..b29555041531 --- /dev/null +++ b/Documentation/admin-guide/devices.rst @@ -0,0 +1,3350 @@ + +Linux allocated devices (4.x+ version) +====================================== + +This list is the Linux Device List, the official registry of allocated +device numbers and ``/dev`` directory nodes for the Linux operating +system. + +The LaTeX version of this document is no longer maintained, nor is +the document that used to reside at lanana.org. This version in the +mainline Linux kernel is the master document. Updates shall be sent +as patches to the kernel maintainers (see the +:ref:`Documentation/SubmittingPatches ` document). +Specifically explore the sections titled "CHAR and MISC DRIVERS", and +"BLOCK LAYER" in the MAINTAINERS file to find the right maintainers +to involve for character and block devices. + +This document is included by reference into the Filesystem Hierarchy +Standard (FHS). The FHS is available from http://www.pathname.com/fhs/. + +Allocations marked (68k/Amiga) apply to Linux/68k on the Amiga +platform only. Allocations marked (68k/Atari) apply to Linux/68k on +the Atari platform only. + +This document is in the public domain. The authors requests, however, +that semantically altered versions are not distributed without +permission of the authors, assuming the authors can be contacted without +an unreasonable effort. + + +.. attention:: + + DEVICE DRIVERS AUTHORS PLEASE READ THIS + + Linux now has extensive support for dynamic allocation of device numbering + and can use ``sysfs`` and ``udev`` (``systemd``) to handle the naming needs. + There are still some exceptions in the serial and boot device area. Before + asking for a device number make sure you actually need one. + + To have a major number allocated, or a minor number in situations + where that applies (e.g. busmice), please submit a patch and send to + the authors as indicated above. + + Keep the description of the device *in the same format + as this list*. The reason for this is that it is the only way we have + found to ensure we have all the requisite information to publish your + device and avoid conflicts. + + Finally, sometimes we have to play "namespace police." Please don't be + offended. We often get submissions for ``/dev`` names that would be bound + to cause conflicts down the road. We are trying to avoid getting in a + situation where we would have to suffer an incompatible forward + change. Therefore, please consult with us **before** you make your + device names and numbers in any way public, at least to the point + where it would be at all difficult to get them changed. + + Your cooperation is appreciated. + +:: + + 0 Unnamed devices (e.g. non-device mounts) + 0 = reserved as null device number + See block major 144, 145, 146 for expansion areas. + + 1 char Memory devices + 1 = /dev/mem Physical memory access + 2 = /dev/kmem Kernel virtual memory access + 3 = /dev/null Null device + 4 = /dev/port I/O port access + 5 = /dev/zero Null byte source + 6 = /dev/core OBSOLETE - replaced by /proc/kcore + 7 = /dev/full Returns ENOSPC on write + 8 = /dev/random Nondeterministic random number gen. + 9 = /dev/urandom Faster, less secure random number gen. + 10 = /dev/aio Asynchronous I/O notification interface + 11 = /dev/kmsg Writes to this come out as pri