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 <mchehab@s-opensource.com>

1 files changed, 300 insertions, 0 deletions

diff --git a/Documentation/admin-guide/oops-tracing.rst b/Documentation/admin-guide/oops-tracing.rst
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+OOPS tracing
+============
+
+.. note::
+
+  ``ksymoops`` is useless on 2.6 or upper.  Please use the Oops in its original
+  format (from ``dmesg``, etc).  Ignore any references in this or other docs to
+  "decoding the Oops" or "running it through ksymoops".
+  If you post an Oops from 2.6+ that has been run through ``ksymoops``,
+  people will just tell you to repost it.
+
+Quick Summary
+-------------
+
+Find the Oops and send it to the maintainer of the kernel area that seems to be
+involved with the problem.  Don't worry too much about getting the wrong person.
+If you are unsure send it to the person responsible for the code relevant to
+what you were doing.  If it occurs repeatably try and describe how to recreate
+it.  That's worth even more than the oops.
+
+If you are totally stumped as to whom to send the report, send it to
+linux-kernel@vger.kernel.org. Thanks for your help in making Linux as
+stable as humanly possible.
+
+Where is the Oops?
+----------------------
+
+Normally the Oops text is read from the kernel buffers by klogd and
+handed to ``syslogd`` which writes it to a syslog file, typically
+``/var/log/messages`` (depends on ``/etc/syslog.conf``).  Sometimes ``klogd``
+dies, in which case you can run ``dmesg > file`` to read the data from the
+kernel buffers and save it.  Or you can ``cat /proc/kmsg > file``, however you
+have to break in to stop the transfer, ``kmsg`` is a "never ending file".
+If the machine has crashed so badly that you cannot enter commands or
+the disk is not available then you have three options :
+
+(1) Hand copy the text from the screen and type it in after the machine
+    has restarted.  Messy but it is the only option if you have not
+    planned for a crash. Alternatively, you can take a picture of
+    the screen with a digital camera - not nice, but better than
+    nothing.  If the messages scroll off the top of the console, you
+    may find that booting with a higher resolution (eg, ``vga=791``)
+    will allow you to read more of the text. (Caveat: This needs ``vesafb``,
+    so won't help for 'early' oopses)
+
+(2) Boot with a serial console (see
+    :ref:`Documentation/serial-console.txt <serial_console>`),
+    run a null modem to a second machine and capture the output there
+    using your favourite communication program.  Minicom works well.
+
+(3) Use Kdump (see Documentation/kdump/kdump.txt),
+    extract the kernel ring buffer from old memory with using dmesg
+    gdbmacro in Documentation/kdump/gdbmacros.txt.
+
+
+Full Information
+----------------
+
+.. note::
+
+  the message from Linus below applies to 2.4 kernel.  I have preserved it
+  for historical reasons, and because some of the information in it still
+  applies.  Especially, please ignore any references to ksymoops.
+
+  ::
+
+        From: Linus Torvalds <torvalds@osdl.org>
+
+        How to track down an Oops.. [originally a mail to linux-kernel]
+
+        The main trick is having 5 years of experience with those pesky oops
+        messages ;-)
+
+Actually, there are things you can do that make this easier. I have two
+separate approaches::
+
+        gdb /usr/src/linux/vmlinux
+        gdb> disassemble <offending_function>
+
+That's the easy way to find the problem, at least if the bug-report is
+well made (like this one was - run through ``ksymoops`` to get the
+information of which function and the offset in the function that it
+happened in).
+
+Oh, it helps if the report happens on a kernel that is compiled with the
+same compiler and similar setups.
+
+The other thing to do is disassemble the "Code:" part of the bug report:
+ksymoops will do this too with the correct tools, but if you don't have
+the tools you can just do a silly program::
+
+        char str[] = "\xXX\xXX\xXX...";
+        main(){}
+
+and compile it with ``gcc -g`` and then do ``disassemble str`` (where the ``XX``
+stuff are the values reported by the Oops - you can just cut-and-paste
+and do a replace of spaces to ``\x`` - that's what I do, as I'm too lazy
+to write a program to automate this all).
+
+Alternatively, you can use the shell script in ``scripts/decodecode``.
+Its usage is::
+
+        decodecode < oops.txt
+
+The hex bytes that follow "Code:" may (in some architectures) have a series
+of bytes that precede the current instruction pointer as well as bytes at and
+following the current instruction pointer.  In some cases, one instruction
+byte or word is surrounded by ``<>`` or ``()``, as in ``<86>`` or ``(f00d)``.
+These ``<>`` or ``()`` markings indicate the current instruction pointer.
+
+Example from i386, split into multiple lines for readability::
+
+        Code: f9 0f 8d f9 00 00 00 8d 42 0c e8 dd 26 11 c7 a1 60 ea 2b f9 8b 50 08 a1
+        64 ea 2b f9 8d 34 82 8b 1e 85 db 74 6d 8b 15 60 ea 2b f9 <8b> 43 04 39 42 54
+        7e 04 40 89 42 54 8b 43 04 3b 05 00 f6 52 c0
+
+Finally, if you want to see where the code comes from, you can do::
+
+        cd /usr/src/linux
+        make fs/buffer.s        # or whatever file the bug happened in
+
+and then you get a better idea of what happens than with the gdb
+disassembly.
+
+Now, the trick is just then to combine all the data you have: the C
+sources (and general knowledge of what it **should** do), the assembly
+listing and the code disassembly (and additionally the register dump you
+also get from the "oops" message - that can be useful to see **what** the
+corrupted pointers were, and when you have the assembler listing you can
+also match the other registers to whatever C expressions they were used
+for).
+
+Essentially, you just look at what doesn't match (in this case it was the
+"Code" disassembly that didn't match with what the compiler generated).
+Then you need to find out **why** they don't match. Often it's simple - you
+see that the code uses a NULL pointer and then you look at the code and
+wonder how the NULL pointer got there, and if it's a valid thing to do
+you just check against it..
+
+Now, if somebody gets the idea that this is time-consuming and requires
+some small amount of concentration, you're right. Which is why I will
+mostly just ignore any panic reports that don't have the symbol table
+info etc looked up: it simply gets too hard to look it up (I have some
+programs to search for specific patterns in the kernel code segment, and
+sometimes I have been able to look up those kinds of panics too, but
+that really requires pretty good knowledge of the kernel just to be able
+to pick out the right sequences etc..)
+
+**Sometimes** it happens that I just see the disassembled code sequence
+from the panic, and I know immediately where it's coming from. That's when
+I get worried that I've been doing this for too long ;-)
+
+                Linus
+
+
+---------------------------------------------------------------------------
+
+Notes on Oops tracing with ``klogd``
+------------------------------------
+
+In order to help Linus and the other kernel developers there has been
+substantial support incorporated into ``klogd`` for processing protection
+faults.  In order to have full support for address resolution at least
+version 1.3-pl3 of the ``sysklogd`` package should be used.
+
+When a protection fault occurs the ``klogd`` daemon automatically
+translates important addresses in the kernel log messages to their
+symbolic equivalents.  This translated kernel message is then
+forwarded through whatever reporting mechanism ``klogd`` is using.  The
+protection fault message can be simply cut out of the message files
+and forwarded to the kernel developers.
+
+Two types of address resolution are performed by ``klogd``.  The first is
+static translation and the second is dynamic translation.  Static
+translation uses the System.map file in much the same manner that
+ksymoops does.  In order to do static translation the ``klogd`` daemon
+must be able to find a system map file at daemon initialization time.
+See the klogd man page for information on how ``klogd`` searches for map
+files.
+
+Dynamic address translation is important when kernel loadable modules
+are being used.  Since memory for kernel modules is allocated from the
+kernel's dynamic memory pools there are no fixed locations for either
+the start of the module or for functions and symbols in the module.
+
+The kernel supports system calls which allow a program to determine
+which modules are loaded and their location in memory.  Using these
+system calls the klogd daemon builds a symbol table which can be used
+to debug a protection fault which occurs in a loadable kernel module.
+
+At the very minimum klogd will provide the name of the module which
+generated the protection fault.  There may be additional symbolic
+information available if the developer of the loadable module chose to
+export symbol information from the module.
+
+Since the kernel module environment can be dynamic there must be a
+mechanism for notifying the ``klogd`` daemon when a change in module
+environment occurs.  There are command line options available which
+allow klogd to signal the currently executing daemon that symbol
+information should be refreshed.  See the ``klogd`` manual page for more
+information.
+
+A patch is included with the sysklogd distribution which modifies the
+``modules-2.0.0`` package to automatically signal klogd whenever a module
+is loaded or unloaded.  Applying this patch provides essentially
+seamless support for debugging protection faults which occur with
+kernel loadable modules.
+
+The following is an example of a protection fault in a loadable module
+processed by ``klogd``::
+
+        Aug 29 09:51:01 blizard kernel: Unable to handle kernel paging request at virtual address f15e97cc
+        Aug 29 09:51:01 blizard kernel: current->tss.cr3 = 0062d000, %cr3 = 0062d000
+        Aug 29 09:51:01 blizard kernel: *pde = 00000000
+        Aug 29 09:51:01 blizard kernel: Oops: 0002
+        Aug 29 09:51:01 blizard kernel: CPU:    0
+        Aug 29 09:51:01 blizard kernel: EIP:    0010:[oops:_oops+16/3868]
+        Aug 29 09:51:01 blizard kernel: EFLAGS: 00010212
+        Aug 29 09:51:01 blizard kernel: eax: 315e97cc   ebx: 003a6f80   ecx: 001be77b   edx: 00237c0c
+        Aug 29 09:51:01 blizard kernel: esi: 00000000   edi: bffffdb3   ebp: 00589f90   esp: 00589f8c
+        Aug 29 09:51:01 blizard kernel: ds: 0018   es: 0018   fs: 002b   gs: 002b   ss: 0018
+        Aug 29 09:51:01 blizard kernel: Process oops_test (pid: 3374, process nr: 21, stackpage=00589000)
+        Aug 29 09:51:01 blizard kernel: Stack: 315e97cc 00589f98 0100b0b4 bffffed4 0012e38e 00240c64 003a6f80 00000001
+        Aug 29 09:51:01 blizard kernel:        00000000 00237810 bfffff00 0010a7fa 00000003 00000001 00000000 bfffff00
+        Aug 29 09:51:01 blizard kernel:        bffffdb3 bffffed4 ffffffda 0000002b 0007002b 0000002b 0000002b 00000036
+        Aug 29 09:51:01 blizard kernel: Call Trace: [oops:_oops_ioctl+48/80] [_sys_ioctl+254/272] [_system_call+82/128]
+        Aug 29 09:51:01 blizard kernel: Code: c7 00 05 00 00 00 eb 08 90 90 90 90 90 90 90 90 89 ec 5d c3
+
+---------------------------------------------------------------------------
+
+::
+
+  Dr. G.W. Wettstein           Oncology Research Div. Computing Facility
+  Roger Maris Cancer Center    INTERNET: greg@wind.rmcc.com
+  820 4th St. N.
+  Fargo, ND  58122
+  Phone: 701-234-7556
+
+
+---------------------------------------------------------------------------
+
+Tainted kernels
+---------------
+
+Some oops reports contain the string **'Tainted: '** after the program
+counter. This indicates that the kernel has been tainted by some
+mechanism.  The string is followed by a series of position-sensitive
+characters, each representing a particular tainted value.
+
+  1) 'G' if all modules loaded have a GPL or compatible license, 'P' if
+     any proprietary module has been loaded.  Modules without a
+     MODULE_LICENSE or with a MODULE_LICENSE that is not recognised by
+     insmod as GPL compatible are assumed to be proprietary.
+
+  2) ``F`` if any module was force loaded by ``insmod -f``, ``' '`` if all
+     modules were loaded normally.
+
+  3) ``S`` if the oops occurred on an SMP kernel running on hardware that
+     hasn't been certified as safe to run multiprocessor.
+     Currently this occurs only on various Athlons that are not
+     SMP capable.
+
+  4) ``R`` if a module was force unloaded by ``rmmod -f``, ``' '`` if all
+     modules were unloaded normally.
+
+  5) ``M`` if any processor has reported a Machine Check Exception,
+     ``' '`` if no Machine Check Exceptions have occurred.
+
+  6) ``B`` if a page-release function has found a bad page reference or
+     some unexpected page flags.
+
+  7) ``U`` if a user or user application specifically requested that the
+     Tainted flag be set, ``' '`` otherwise.
+
+  8) ``D`` if the kernel has died recently, i.e. there was an OOPS or BUG.
+
+  9) ``A`` if the ACPI table has been overridden.
+
+ 10) ``W`` if a warning has previously been issued by the kernel.
+     (Though some warnings may set more specific taint flags.)
+
+ 11) ``C`` if a staging driver has been loaded.
+
+ 12) ``I`` if the kernel is working around a severe bug in the platform
+     firmware (BIOS or similar).
+
+ 13) ``O`` if an externally-built ("out-of-tree") module has been loaded.
+
+ 14) ``E`` if an unsigned module has been loaded in a kernel supporting
+     module signature.
+
+ 15) ``L`` if a soft lockup has previously occurred on the system.
+
+ 16) ``K`` if the kernel has been live patched.
+
+The primary reason for the **'Tainted: '** string is to tell kernel
+debuggers if this is a clean kernel or if anything unusual has
+occurred.  Tainting is permanent: even if an offending module is
+unloaded, the tainted value remains to indicate that the kernel is not
+trustworthy.