Provided by: makedumpfile_1.6.5-1ubuntu1~18.04.7_amd64 bug

NAME

       makedumpfile - make a small dumpfile of kdump

SYNOPSIS

       makedumpfile    [OPTION] [-x VMLINUX|-i VMCOREINFO] VMCORE DUMPFILE
       makedumpfile -F [OPTION] [-x VMLINUX|-i VMCOREINFO] VMCORE
       makedumpfile   [OPTION] -x VMLINUX [--config FILTERCONFIGFILE] [--eppic EPPICMACRO] VMCORE
       DUMPFILE
       makedumpfile -R DUMPFILE
       makedumpfile --split  [OPTION]  [-x  VMLINUX|-i  VMCOREINFO]  VMCORE  DUMPFILE1  DUMPFILE2
       [DUMPFILE3 ..]
       makedumpfile [OPTION] [-x VMLINUX|-i VMCOREINFO] --num-threads THREADNUM VMCORE DUMPFILE
       makedumpfile --reassemble DUMPFILE1 DUMPFILE2 [DUMPFILE3 ..] DUMPFILE
       makedumpfile -g VMCOREINFO -x VMLINUX
       makedumpfile    [OPTION] [--xen-syms XEN-SYMS|--xen-vmcoreinfo VMCOREINFO] VMCORE DUMPFILE
       makedumpfile --dump-dmesg [--partial-dmesg] [-x VMLINUX|-i VMCOREINFO] VMCORE LOGFILE
       makedumpfile    [OPTION] -x VMLINUX --diskset=VMCORE1 --diskset=VMCORE2 [--diskset=VMCORE3
       ..] DUMPFILE
       makedumpfile -h
       makedumpfile -v

DESCRIPTION

       With kdump, the memory image of the first kernel (called "panicked kernel") can  be  taken
       as  /proc/vmcore  while  the  second kernel (called "kdump kernel" or "capture kernel") is
       running. This document represents /proc/vmcore  as  VMCORE.  makedumpfile  makes  a  small
       DUMPFILE by compressing dump data or by excluding unnecessary pages for analysis, or both.
       makedumpfile needs the first kernel's  debug  information,  so  that  it  can  distinguish
       unnecessary  pages by analyzing how the first kernel uses the memory.  The information can
       be taken from VMLINUX or VMCOREINFO.

       makedumpfile can exclude the following types of pages while copying  VMCORE  to  DUMPFILE,
       and a user can choose which type of pages will be excluded.
       - Pages filled with zero
       - Cache pages without private flag (non-private cache)
       - Cache pages with private flag (private cache)
       - User process data pages
       - Free pages

       makedumpfile  provides  two  DUMPFILE  formats  (the  ELF  format and the kdump-compressed
       format). By default, makedumpfile makes a DUMPFILE in  the  kdump-compressed  format.  The
       kdump-compressed  format  is  readable  only with the crash utility, and it can be smaller
       than the ELF format because of the compression support. The ELF format  is  readable  with
       GDB  and  the  crash  utility.   If  a  user  wants  to use GDB, DUMPFILE format has to be
       explicitly specified to be the ELF format.

       Apart from the exclusion of unnecessary pages mentioned above, makedumpfile allows user to
       filter  out  targeted  kernel  data.  The  filter  config  file  can  be  used  to specify
       kernel/module symbols and its members that need to  be  filtered  out  through  the  erase
       command  syntax.  makedumpfile  reads  the  filter  config  and  builds the list of memory
       addresses and its sizes after  processing  filter  commands.  The  memory  locations  that
       require  to  be  filtered  out  are then poisoned with character 'X' (58 in Hex). Refer to
       makedumpfile.conf(5) for file format.

       Eppic macros can also be used to specify kernel symbols and its members that  need  to  be
       filtered.  Eppic  provides  C  semantics including language constructs such as conditional
       statements, logical and arithmetic operators, functions,  nested  loops  to  traverse  and
       erase   kernel   data.   --eppic   requires   eppic_makedumpfile.so   and  eppic  library.
       eppic_makedumpfile.so   can   be   built    from    makedumpfile    source.    Refer    to
       http://code.google.com/p/eppic/ to build eppic library libeppic.a and for more information
       on writing eppic macros.

       To analyze the first kernel's memory usage, makedumpfile can refer to  VMCOREINFO  instead
       of  VMLINUX.  VMCOREINFO  contains  the  first kernel's information (structure size, field
       offset, etc.), and VMCOREINFO is small enough to be  included  into  the  second  kernel's
       initrd.
       If  the  second  kernel  is  running  on  its  initrd without mounting a root file system,
       makedumpfile cannot refer to VMLINUX because the second kernel's initrd cannot  include  a
       large  file  like VMLINUX. To solve the problem, makedumpfile makes VMCOREINFO beforehand,
       and it refers to VMCOREINFO instead of VMLINUX while the second kernel is running.
       VMCORE has contained VMCOREINFO since linux-2.6.24, and a user does not  need  to  specify
       neither -x nor -i option.

       If  the  second  kernel  is running on its initrd without mounting any file system, a user
       needs to transport the dump data to a remote host. To transport  the  dump  data  by  SSH,
       makedumpfile  outputs  the  dump data in the intermediate format (the flattened format) to
       the standard output. By piping the output data to SSH, a user can transport the dump  data
       to  a  remote  host.  Note that analysis tools (crash utility before version 5.1.2 or GDB)
       cannot read the flattened format directly, so on a remote host the received  data  in  the
       flattened  format needs to be rearranged to a readable DUMPFILE format by makedumpfile (or
       makedumpfile-R.pl).

       makedumpfile can read a DUMPFILE in the kdump-compressed format instead of VMCORE and  re-
       filter  it. This feature is useful in situation that users need to reduce the file size of
       DUMPFILE for sending it somewhere by ftp/scp/etc. (If all of the  page  types,  which  are
       specified  by  a  new  dump_level,  are  excluded from an original DUMPFILE already, a new
       DUMPFILE is the same as an original DUMPFILE.)
       For example, makedumpfile can  create  a  DUMPFILE  of  dump_level  31  from  the  one  of
       dump_level 3 like the following:
       Example:
       # makedumpfile -c -d 3 /proc/vmcore dumpfile.1
       # makedumpfile -c -d 31 dumpfile.1 dumpfile.2

       makedumpfile can read VMCORE(s) in three kinds of sadump formats: single partition format,
       diskset format and media backup format, and can convert each of them into kdump-compressed
       format  with  filtering  and  compression  processing.  Note that for VMCORE(s) created by
       sadump, you always need to pass VMLINUX with -x option. Also,  to  pass  multiple  VMCOREs
       created on diskset configuration, you need to use --diskset option.

OPTIONS

       -c,-l,-p
              Compress  dump  data  by  each  page using zlib for -c option, lzo for -l option or
              snappy for -p option.  (-l option needs USELZO=on and -p option needs  USESNAPPY=on
              when building)
              A  user  cannot specify this option with -E option, because the ELF format does not
              support compressed data.
              Example:
              # makedumpfile -c -d 31 -x vmlinux /proc/vmcore dumpfile

       -d dump_level
              Specify the type of unnecessary page for analysis.
              Pages of the specified type are not copied to DUMPFILE. The page type marked in the
              following  table is excluded. A user can specify multiple page types by setting the
              sum of each page type for dump_level. The maximum of dump_level is 31. Note that  a
              dump_level  for  Xen  dump filtering is 0 or 1 on a machine other than x86_64. On a
              x86_64 machine, even 2 or bigger dump  level  will  be  effective  if  you  specify
              domain-0's vmlinux with -x option.  Then the pages are excluded only from domain-0.
              If  specifying multiple dump_levels with the delimiter ',', makedumpfile retries to
              create a DUMPFILE by other dump_level when "No space on device" error happens.  For
              example,  if  dump_level  is  "11,31"  and  makedumpfile  fails  by  dump_level 11,
              makedumpfile retries it by dump_level 31.
              Example:
              # makedumpfile -d 11 -x vmlinux /proc/vmcore dumpfile
              # makedumpfile -d 11,31 -x vmlinux /proc/vmcore dumpfile
              Base level:
              dump_level consists of five bits, so there are five base levels to specify the type
              of unnecessary page.
                    1 : Exclude the pages filled with zero.
                    2 : Exclude the non-private cache pages.
                    4 : Exclude all cache pages.
                    8 : Exclude the user process data pages.
                   16 : Exclude the free pages.

              Here is the all combinations of the bits.

                     |      |non-   |       |      |
                dump | zero |private|private| user | free
               level | page |cache  |cache  | data | page
              -------+------+-------+-------+------+------
                   0 |      |       |       |      |
                   1 |  X   |       |       |      |
                   2 |      |   X   |       |      |
                   3 |  X   |   X   |       |      |
                   4 |      |   X   |   X   |      |
                   5 |  X   |   X   |   X   |      |
                   6 |      |   X   |   X   |      |
                   7 |  X   |   X   |   X   |      |
                   8 |      |       |       |  X   |
                   9 |  X   |       |       |  X   |
                  10 |      |   X   |       |  X   |
                  11 |  X   |   X   |       |  X   |
                  12 |      |   X   |   X   |  X   |
                  13 |  X   |   X   |   X   |  X   |
                  14 |      |   X   |   X   |  X   |
                  15 |  X   |   X   |   X   |  X   |
                  16 |      |       |       |      |  X
                  17 |  X   |       |       |      |  X
                  18 |      |   X   |       |      |  X
                  19 |  X   |   X   |       |      |  X
                  20 |      |   X   |   X   |      |  X
                  21 |  X   |   X   |   X   |      |  X
                  22 |      |   X   |   X   |      |  X
                  23 |  X   |   X   |   X   |      |  X
                  24 |      |       |       |  X   |  X
                  25 |  X   |       |       |  X   |  X
                  26 |      |   X   |       |  X   |  X
                  27 |  X   |   X   |       |  X   |  X
                  28 |      |   X   |   X   |  X   |  X
                  29 |  X   |   X   |   X   |  X   |  X
                  30 |      |   X   |   X   |  X   |  X
                  31 |  X   |   X   |   X   |  X   |  X

       -E     Create DUMPFILE in the ELF format.
              This  option  cannot  be  specified  with the -c, -l or -p options, because the ELF
              format does not support compressed data.
              Example:
              # makedumpfile -E -d 31 -x vmlinux /proc/vmcore dumpfile

       -f     Force existing DUMPFILE to be overwritten and mem-usage to work with  older  kernel
              as well.
              Example:
              # makedumpfile -f -d 31 -x vmlinux /proc/vmcore dumpfile
              This command overwrites DUMPFILE even if it already exists.
              # makedumpfile -f --mem-usage /proc/kcore
              Kernel version lesser than v4.11 will not work with --mem-usage functionality until
              it has been patched with upstream  commit  464920104bf7.   Therefore  if  you  have
              patched your older kernel then use -f.

       -x VMLINUX
              Specify  the  first  kernel's  VMLINUX  with debug information to analyze the first
              kernel's memory usage.
              This option is necessary if VMCORE does not contain VMCOREINFO, [-i VMCOREINFO]  is
              not specified, and dump_level is 2 or more.
              The page size of the first kernel and the second kernel should match.
              Example:
              # makedumpfile -d 31 -x vmlinux /proc/vmcore dumpfile

       -i VMCOREINFO
              Specify  VMCOREINFO  instead  of  VMLINUX  for  analyzing the first kernel's memory
              usage.
              VMCOREINFO should be made  beforehand  by  makedumpfile  with  -g  option,  and  it
              contains the first kernel's information.
              This option is necessary if VMCORE does not contain VMCOREINFO, [-x VMLINUX] is not
              specified, and dump_level is 2 or more.
              Example:
              # makedumpfile -d 31 -i vmcoreinfo /proc/vmcore dumpfile

       -g VMCOREINFO
              Generate VMCOREINFO from the first kernel's VMLINUX with debug information.
              VMCOREINFO must be generated on the system that is running the first  kernel.  With
              -i  option,  a  user  can  specify VMCOREINFO generated on the other system that is
              running the same first kernel. [-x VMLINUX] must be specified.
              Example:
              # makedumpfile -g vmcoreinfo -x vmlinux

       --config FILTERCONFIGFILE
              Used in conjunction with -x VMLINUX option,  to  specify  the  filter  config  file
              FILTERCONFIGFILE  that  contains  erase  commands to filter out desired kernel data
              from vmcore while creating DUMPFILE. For filter  command  syntax  please  refer  to
              makedumpfile.conf(5).

       --eppic EPPICMACRO
              Used  in  conjunction  with -x VMLINUX option, to specify the eppic macro file that
              contains filter rules or directory that contains eppic macro files  to  filter  out
              desired  kernel  data  from  vmcore  while  creating  DUMPFILE.   When directory is
              specified, all the eppic macros in the directory are processed.

       -F     Output  the  dump  data  in  the  flattened  format  to  the  standard  output  for
              transporting the dump data by SSH.
              Analysis  tools  (crash  utility  before  version  5.1.2  or  GDB)  cannot read the
              flattened format directly. For analysis, the dump  data  in  the  flattened  format
              should  be  rearranged  to  a  normal DUMPFILE (readable with analysis tools) by -R
              option. By which option is specified with -F option, the format of  the  rearranged
              DUMPFILE is fixed.  In other words, it is impossible to specify the DUMPFILE format
              when the dump data is rearranged with -R option. If specifying -E  option  with  -F
              option,  the  format of the rearranged DUMPFILE is the ELF format. Otherwise, it is
              the kdump-compressed format. All the messages are output to standard  error  output
              by -F option because standard output is used for the dump data.
              Example:
              # makedumpfile -F -c -d 31 -x vmlinux /proc/vmcore \
              | ssh user@host "cat > dumpfile.tmp"
              # makedumpfile -F -c -d 31 -x vmlinux /proc/vmcore \
              | ssh user@host "makedumpfile -R dumpfile"
              # makedumpfile -F -E -d 31 -i vmcoreinfo  /proc/vmcore \
              | ssh user@host "makedumpfile -R dumpfile"
              # makedumpfile -F -E --xen-vmcoreinfo VMCOREINFO /proc/vmcore \
              | ssh user@host "makedumpfile -R dumpfile"

       -R     Rearrange the dump data in the flattened format from the standard input to a normal
              DUMPFILE (readable with analysis tools).
              Example:
              # makedumpfile -R dumpfile < dumpfile.tmp
              # makedumpfile -F -d 31 -x vmlinux /proc/vmcore \
              | ssh user@host "makedumpfile -R dumpfile"

              Instead of using -R option, a perl script "makedumpfile-R.pl" rearranges  the  dump
              data  in  the  flattened format to a normal DUMPFILE, too. The perl script does not
              depend on architecture, and most systems have perl command.  Even if a remote  host
              does  not  have  makedumpfile,  it  is  possible  to rearrange the dump data in the
              flattened format to a readable DUMPFILE on a remote host by running this script.
              Example:
              # makedumpfile -F -d 31 -x vmlinux /proc/vmcore \
              | ssh user@host "makedumpfile-R.pl dumpfile"

       --split
              Split the dump data to multiple DUMPFILEs in parallel. If specifying  DUMPFILEs  on
              different  storage  devices,  a device can share I/O load with other devices and it
              reduces time for saving the dump data. The file size of each  DUMPFILE  is  smaller
              than  the  system  memory  size  which  is divided by the number of DUMPFILEs. This
              feature supports only the kdump-compressed format.
              Example:
              # makedumpfile --split -d 31 -x vmlinux /proc/vmcore dumpfile1 dumpfile2

       --num-threads THREADNUM
              Using multiple threads to read and compress data of each page in parallel.  And  it
              will  reduces time for saving DUMPFILE.  Note that if the usable cpu number is less
              than the thread number, it may lead to great performance degradation.  This feature
              only   supports   creating  DUMPFILE  in  kdump-comressed  format  from  VMCORE  in
              kdump-compressed format or elf format.
              Example:
              # makedumpfile -d 31 --num-threads 4 /proc/vmcore dumpfile

       --reassemble
              Reassemble multiple DUMPFILEs, which  are  created  by  --split  option,  into  one
              DUMPFILE.  dumpfile1  and  dumpfile2 are reassembled into dumpfile on the following
              example.
              Example:
              # makedumpfile --reassemble dumpfile1 dumpfile2 dumpfile

       -b <order>
              Cache 2^order pages in ram when generating DUMPFILE before writing to output.   The
              default value is 4.

       --cyclic-buffer buffer_size
              Specify  the  buffer size in kilo bytes for bitmap data.  Filtering processing will
              be divided into multi cycles to fix the memory consumption, the number of cycles is
              represented as:

                  num_of_cycles = system_memory / (buffer_size * 1024 * bit_per_bytes * page_size
              )

              The lesser number of cycles, the faster working speed  is  expected.   By  default,
              buffer_size  will  be  calculated automatically depending on system memory size, so
              ordinary users don't need to specify this option.

              Example:
              # makedumpfile --cyclic-buffer 1024 -d 31 -x vmlinux /proc/vmcore dumpfile

       --splitblock-size splitblock_size
              Specify  the  splitblock  size  in  kilo  bytes  for  analysis  with  --split.   If
              --splitblock N is specified, difference of each splitted dumpfile size is at most N
              kilo bytes.
              Example:
              # makedumpfile  --splitblock-size  1024  -d  31  -x  vmlinux  --split  /proc/vmcore
              dumpfile1 dumpfile2

       --work-dir
              Specify  the working directory for the temporary bitmap file.  If this option isn't
              specified, the bitmap will be saved on memory.  Filtering processing has  to  do  2
              pass scanning to fix the memory consumption, but it can be avoided by using working
              directory on file system.  So if you specify this option, the filtering  speed  may
              be bit faster.

              Example:
              # makedumpfile --work-dir /tmp -d 31 -x vmlinux /proc/vmcore dumpfile

       --non-mmap
              Never  use  mmap(2) to read VMCORE even if it supports mmap(2).  Generally, reading
              VMCORE with mmap(2) is faster than without it, so  ordinary  users  don't  need  to
              specify this option.  This option is mainly for debugging.
              Example:
              # makedumpfile --non-mmap -d 31 -x vmlinux /proc/vmcore dumpfile

       --xen-syms XEN-SYMS
              Specify  the  XEN-SYMS  with  debug  information to analyze the xen's memory usage.
              This option extracts the part of xen and domain-0.
              Example:
              # makedumpfile -E --xen-syms xen-syms /proc/vmcore dumpfile

       --xen-vmcoreinfo VMCOREINFO
              Specify VMCOREINFO instead of XEN-SYMS for analyzing the xen's memory usage.
              VMCOREINFO should be made  beforehand  by  makedumpfile  with  -g  option,  and  it
              contains the xen's information.
              Example:
              # makedumpfile -E --xen-vmcoreinfo VMCOREINFO /proc/vmcore dumpfile

       -X     Exclude all the user domain pages from Xen kdump's VMCORE, and extracts the part of
              xen and domain-0. If VMCORE contains VMCOREINFO for Xen, it  is  not  necessary  to
              specify --xen-syms and --xen-vmcoreinfo.
              Example:
              # makedumpfile -E -X /proc/vmcore dumpfile

       --xen_phys_start xen_phys_start_address
              This  option  is  only  for x86_64.  Specify the xen_phys_start_address, if the xen
              code/data is relocatable and VMCORE does not contain xen_phys_start_address in  the
              CRASHINFO.   xen_phys_start_address  can be taken from the line of "Hypervisor code
              and data" in /proc/iomem. For example, specify 0xcee00000 as xen_phys_start_address
              if /proc/iomem is the following:
                -------------------------------------------------------
                # cat /proc/iomem
                ...
                  cee00000-cfd99999 : Hypervisor code and data
                ...
                -------------------------------------------------------

              Example:
              # makedumpfile -E -X --xen_phys_start 0xcee00000 /proc/vmcore dumpfile

       --message-level message_level
              Specify the message types.
              Users  can  restrict  outputs printed by specifying message_level with this option.
              The message type marked with an X in the following table is printed.  For  example,
              according  to  the  table,  specifying 7 as message_level means progress indicator,
              common message, and error message are printed, and this is a  default  value.  Note
              that the maximum value of message_level is 31.

               message | progress | common  | error   | debug   | report
               level   | indicator| message | message | message | message
              ---------+----------+---------+---------+---------+---------
                     0 |          |         |         |         |
                     1 |    X     |         |         |         |
                     2 |          |    X    |         |         |
                     3 |    X     |    X    |         |         |
                     4 |          |         |    X    |         |
                     5 |    X     |         |    X    |         |
                     6 |          |    X    |    X    |         |
                   * 7 |    X     |    X    |    X    |         |
                     8 |          |         |         |    X    |
                     9 |    X     |         |         |    X    |
                    10 |          |    X    |         |    X    |
                    11 |    X     |    X    |         |    X    |
                    12 |          |         |    X    |    X    |
                    13 |    X     |         |    X    |    X    |
                    14 |          |    X    |    X    |    X    |
                    15 |    X     |    X    |    X    |    X    |
                    16 |          |         |         |         |    X
                    17 |    X     |         |         |         |    X
                    18 |          |    X    |         |         |    X
                    19 |    X     |    X    |         |         |    X
                    20 |          |         |    X    |         |    X
                    21 |    X     |         |    X    |         |    X
                    22 |          |    X    |    X    |         |    X
                    23 |    X     |    X    |    X    |         |    X
                    24 |          |         |         |    X    |    X
                    25 |    X     |         |         |    X    |    X
                    26 |          |    X    |         |    X    |    X
                    27 |    X     |    X    |         |    X    |    X
                    28 |          |         |    X    |    X    |    X
                    29 |    X     |         |    X    |    X    |    X
                    30 |          |    X    |    X    |    X    |    X
                    31 |    X     |    X    |    X    |    X    |    X

       --vtop virtual_address
              This option is useful, when user debugs the translation problem of virtual address.
              If specifing virtual_address, its physical address is printed. It  makes  debugging
              easy  by  comparing  the output of this option with the one of "vtop" subcommand of
              the crash utility.  "--vtop" option only prints the translation output, and it does
              not affect the dumpfile creation.

       --dump-dmesg
              This  option overrides the normal behavior of makedumpfile.  Instead of compressing
              and filtering a VMCORE to make it smaller, it simply extracts the dmesg log from  a
              VMCORE  and  writes  it  to  the  specified  LOGFILE.  If a VMCORE does not contain
              VMCOREINFO for dmesg, it is necessary to specfiy [-x VMLINUX] or [-i VMCOREINFO].

              Example:
              # makedumpfile --dump-dmesg /proc/vmcore dmesgfile
              # makedumpfile --dump-dmesg -x vmlinux /proc/vmcore dmesgfile

       --partial-dmesg
              This option will make --dump-dmesg extract only dmesg logs since  that  buffer  was
              last cleared on the crashed kernel, through "dmesg --clear" for example.

       --mem-usage
              This  option is currently supported on x86_64, arm64, ppc64 and s390x.  This option
              is used to show the page numbers of current system in different use. It  should  be
              executed  in  1st  kernel.  By  the  help  of this, user can know how many pages is
              dumpable when different dump_level is specified. It analyzes the 'System  Ram'  and
              'kernel  text' program segment of /proc/kcore excluding the crashkernel range, then
              calculates  the  page  number  of  different  kind  per  vmcoreinfo.  So  currently
              /proc/kcore need be specified explicitly.

              Example:
              # makedumpfile --mem-usage /proc/kcore

       --diskset=VMCORE
              Specify multiple VMCOREs created on sadump diskset configuration the same number of
              times as the number of VMCOREs in increasing order from left to right.  VMCOREs are
              assembled into a single DUMPFILE.

              Example:
              # makedumpfile -x vmlinux --diskset=vmcore1 --diskset=vmcore2 dumpfile

       -D     Print debugging message.

       -h (--help)
              Show help message and LZO/snappy support status (enabled/disabled).

       -v     Show the version of makedumpfile.

ENVIRONMENT VARIABLES

       TMPDIR  This environment variable is used in 1st kernel environment for a temporary memory
               bitmap file.  If your machine has a lots of memory and  you  use  small  tmpfs  on
               /tmp,  makedumpfile can fail for a little memory because makedumpfile makes a very
               large temporary memory bitmap file in this case. To avoid this failure, you should
               specify --work-dir option to use file system on storage for the bitmap file.

DIAGNOSTICS

       makedumpfile exits with the following value.

       0 : makedumpfile succeeded.

       1 : makedumpfile failed without the following reasons.

       2 : makedumpfile failed due to the different version between  VMLINUX and VMCORE.

AUTHORS

       Written by Masaki Tachibana, and Ken'ichi Ohmichi.

SEE ALSO

       crash(8), gdb(1), kexec(8), makedumpfile.conf(5)