Provided by: crash_3.8-2.1-3_i386 bug


       crash - A kernel debugging utility, supporting gdb like syntax.


       crash [-h [opt]] [-v] [-s] [-i file] [-d num] [-S] [mapfile] [namelist]


       This manual page documents briefly the crash command.  This manual page
       was  written for the Debian GNU/Linux distribution because the original
       program  does  not  have  a  manual  page.   Instead,  it  has   online
       documentation; see below.

       crash  is  a self-contained tool that can be used to investigate either
       live systems, kernel core dumps created from the Kernel Core Dump patch
       offered  by Mission Critical Linux, or kernel core dumps created by the
       LKCD patch offered by SGI.

       The tool is loosely based on the  SVR4  crash  command,  but  has  been
       completely integrated with gdb in order to be able to display formatted
       kernel data structures, disassemble source code, etc.

       The current set of available commands consist  of  common  kernel  core
       analysis  tools  such  as  a context-specific stack traces, source code
       disassembly, kernel variable displays, memory display, dumps of linked-
       lists, etc.  In addition, any gdb command may be entered, which in turn
       will be passed onto the gdb module for execution.

       There are several commands  that  delve  deeper  into  specific  kernel
       subsystems,  which  also  serve  as  templates for kernel developers to
       create new commands for  analysis  of  a  specific  area  of  interest.
       Adding  a new command is a simple affair, and a quick recompile adds it
       to the command menu.

       The  intent  is  to  make  the  tool  independent  of   Linux   version
       dependencies,  building  in recognition of major kernel code changes so
       as to  adapt  to  new  kernel  versions,  while  maintaining  backwards


       Most  options  are  documented internal to crash.  After running crash,
       the help command will give you all the information you need.

              The [namelist] argument is a pathname to an uncompressed  kernel
              image  (a  vmlinux  file)  that  has been compiled with the "-g"
              switch, or that has an accessible, associated,  debuginfo  file.
              If  the  [dumpfile]  argument  is  entered,  then the [namelist]
              argument must be entered  If  the  [namelist]  argument  is  not
              entered  when running on a live system, a search will be made in
              several typical directories for for a kernel namelist file  that
              matches the live system.

              The  [dumpfile]  argument  is a pathname to a kernel memory core
              dump file.  If the  [dumpfile]  argument  is  not  entered,  the
              session will be invoked on the live system using /dev/mem, which
              usually requires root privileges.

              If the  live  system  kernel,  or  the  kernel  from  which  the
              [dumpfile]  was  derived,  was  not compiled with the -g switch,
              then  the  additional  [mapfile]  argument  is  required.    The
              [mapfile]   argument   may  consist  of  either  the  associated
     file, or the non-debug kernel namelist.  However,  if
              the  [mapfile]  argument  is  used, then the [namelist] argument
              must be a kernel namelist of a similar kernel version  that  was
              built with the -g switch.

       -S     Use "/boot/" as the [mapfile].

              Examples when running on a live system:

                $ crash
                $ crash /usr/tmp/vmlinux
                $ crash /boot/ vmlinux.dbg
                $ crash -S vmlinux.dbg
                $ crash vmlinux vmlinux.dbg

              Examples when running on a dumpfile:

                $ crash vmlinux vmcore
                $ crash /boot/ vmlinux.dbg vmcore
                $ crash -S vmlinux.dbg vmcore
                $ crash vmlinux vmlinux.dbg vmcore

       -h [opt]
              The  -h  option  alone  displays  a  help message.  If the [opt]
              argument is a crash command name, the help page for that command
              is  displayed.   If  the  string  "input"  is  entered,  a  page
              describing the various  crash  command  line  input  options  is
              displayed.  If the string "output" is entered, a page describing
              command line output options is displayed.

       -v     Display the versions of crash and gdb making up this executable.

       -s     Do  not  display any version, GPL, or crash initialization data;
              proceed directly to the "crash>" prompt.

       -i file
              Execute the crash command(s) in [file] prior  to  accepting  any
              user input from the "crash>" prompt.

       -d num Set  crash  debug  level [num].  The higher the number, the more
              debug data will be printed during crash runtime.




       This manual page was written by Josh Huber  <>,  for  the
       Debian GNU/Linux system (but may be used by others).

                                 June 23, 2004                        CRASH(8)