makedumpfile.8

.TH MAKEDUMPFILE 8 "16 Jan 2020" "makedumpfile v1.6.7" "Linux System Administrator's Manual"
.SH NAME
makedumpfile \- make a small dumpfile of kdump
.SH SYNOPSIS
\fBmakedumpfile\fR    [\fIOPTION\fR] [\-x \fIVMLINUX\fR|\-i \fIVMCOREINFO\fR] \fIVMCORE\fR \fIDUMPFILE\fR
.br
\fBmakedumpfile\fR \-F [\fIOPTION\fR] [\-x \fIVMLINUX\fR|\-i \fIVMCOREINFO\fR] \fIVMCORE\fR
.br
\fBmakedumpfile\fR   [\fIOPTION\fR] \-x \fIVMLINUX\fR [\-\-config \fIFILTERCONFIGFILE\fR] [\-\-eppic \fIEPPICMACRO\fR] \fIVMCORE\fR \fIDUMPFILE\fR
.br
\fBmakedumpfile\fR \-R \fIDUMPFILE\fR
.br
\fBmakedumpfile\fR \-\-split [\fIOPTION\fR] [\-x \fIVMLINUX\fR|\-i \fIVMCOREINFO\fR] \fIVMCORE\fR \fIDUMPFILE1\fR \fIDUMPFILE2\fR [\fIDUMPFILE3\fR ..]
.br
\fBmakedumpfile\fR [\fIOPTION\fR] [\-x \fIVMLINUX\fR|\-i \fIVMCOREINFO\fR] \-\-num\-threads \fITHREADNUM\fR \fIVMCORE\fR \fIDUMPFILE\fR
.br
\fBmakedumpfile\fR \-\-reassemble \fIDUMPFILE1\fR \fIDUMPFILE2\fR [\fIDUMPFILE3\fR ..] \fIDUMPFILE\fR
.br
\fBmakedumpfile\fR \-g \fIVMCOREINFO\fR \-x \fIVMLINUX\fR
.br
\fBmakedumpfile\fR    [\fIOPTION\fR] [\-\-xen-syms \fIXEN-SYMS\fR|\-\-xen-vmcoreinfo \fIVMCOREINFO\fR] \fIVMCORE\fR \fIDUMPFILE\fR
.br
\fBmakedumpfile\fR \-\-dump-dmesg [\-\-partial-dmesg] [\-x \fIVMLINUX\fR|\-i \fIVMCOREINFO\fR] \fIVMCORE\fR \fILOGFILE\fR
.br
\fBmakedumpfile\fR    [\fIOPTION\fR] \-x \fIVMLINUX\fR \-\-diskset=\fIVMCORE1\fR \-\-diskset=\fIVMCORE2\fR [\-\-diskset=\fIVMCORE3\fR ..] \fIDUMPFILE\fR
.br
.B makedumpfile
\-h
.br
.B makedumpfile
\-v
.br
.SH DESCRIPTION
.PP
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
\fIVMCORE\fR. makedumpfile makes a small \fIDUMPFILE\fR 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 \fIVMLINUX\fR or \fIVMCOREINFO\fR.
.PP
makedumpfile can exclude the following types of pages while copying
\fIVMCORE\fR to \fIDUMPFILE\fR, and a user can choose which type of pages will
be excluded.
.br
.B \- Pages filled with zero
.br
.B \- Cache pages without private flag (non-private cache)
.br
.B \- Cache pages with private flag (private cache)
.br
.B \- User process data pages
.br
.B \- Free pages
.PP
makedumpfile provides two \fIDUMPFILE\fR formats (the ELF format and the
kdump\-compressed format). By default, makedumpfile makes a \fIDUMPFILE\fR 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, \fIDUMPFILE\fR format has to be explicitly
specified to be the ELF format.
.PP
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
\fBmakedumpfile.conf(5)\fR for file format.
.PP
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
\fBeppic_makedumpfile.so\fR and eppic library. \fBeppic_makedumpfile.so\fR
can be built from makedumpfile source. Refer to
\fBhttp://code.google.com/p/eppic/\fR to build eppic library \fBlibeppic.a\fR
and for more information on writing eppic macros.
.PP
To analyze the first kernel's memory usage, makedumpfile can refer to
\fIVMCOREINFO\fR instead of \fIVMLINUX\fR. \fIVMCOREINFO\fR contains the first
kernel's information (structure size, field offset, etc.), and \fIVMCOREINFO\fR
is small enough to be included into the second kernel's initrd.
.br
If the second kernel is running on its initrd without mounting a root file
system, makedumpfile cannot refer to \fIVMLINUX\fR because the second kernel's
initrd cannot include a large file like \fIVMLINUX\fR. To solve the problem,
makedumpfile makes \fIVMCOREINFO\fR beforehand, and it refers to
\fIVMCOREINFO\fR instead of \fIVMLINUX\fR while the second kernel is running.
.br
\fIVMCORE\fR has contained \fIVMCOREINFO\fR since linux-2.6.24, and a user does
not need to specify neither -x nor -i option.
.PP
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 \fIDUMPFILE\fR format by makedumpfile (or makedumpfile\-R.pl).
.PP
makedumpfile can read a \fIDUMPFILE\fR in the kdump-compressed format instead
of \fIVMCORE\fR and re-filter it. This feature is useful in situation that
users need to reduce the file size of \fIDUMPFILE\fR 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 \fIDUMPFILE\fR already, a new \fIDUMPFILE\fR is the
same as an original \fIDUMPFILE\fR.)
.br
For example, makedumpfile can create a \fIDUMPFILE\fR of dump_level 31 from the
one of dump_level 3 like the following:
.br
.B Example:
.br
# makedumpfile \-c \-d 3 /proc/vmcore dumpfile.1
.br
# makedumpfile \-c \-d 31 dumpfile.1 dumpfile.2
.PP
makedumpfile can read \fIVMCORE\fR(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 \fIVMCORE\fR(s)
created by sadump, you always need to pass \fIVMLINUX\fR with -x
option. Also, to pass multiple \fIVMCORE\fRs created on diskset
configuration, you need to use --diskset option.

.PP
.SH OPTIONS

.TP
\fB\-c,\-l,\-p\fR
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)
.br
A user cannot specify this option with \-E option, because the ELF format does
not support compressed data.
.br
.B Example:
.br
# makedumpfile \-c \-d 31 \-x vmlinux /proc/vmcore dumpfile

.TP
.BI \-d \ dump_level
Specify the type of unnecessary page for analysis.
.br
Pages of the specified type are not copied to \fIDUMPFILE\fR. 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 \fIvmlinux\fR with \-x option.
Then the pages are excluded only from domain-0.
.br
If specifying multiple dump_levels with the delimiter ',', makedumpfile retries
to create a \fIDUMPFILE\fR 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.
.br
.B Example:
.br
# makedumpfile \-d 11 \-x vmlinux /proc/vmcore dumpfile
.br
# makedumpfile \-d 11,31 \-x vmlinux /proc/vmcore dumpfile
.br
.B Base level:
.br
dump_level consists of five bits, so there are five base levels to specify the type of unnecessary page.
.br
	\fB 1\fR :	Exclude the pages filled with zero.
.br
	\fB 2\fR :	Exclude the non-private cache pages.
.br
	\fB 4\fR :	Exclude all cache pages.
.br
	\fB 8\fR :	Exclude the user process data pages.
.br
	\fB16\fR :	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
.br
\-\-\-\-\-\-\-+\-\-\-\-\-\-+\-\-\-\-\-\-\-+\-\-\-\-\-\-\-+\-\-\-\-\-\-+\-\-\-\-\-\-
     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


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

.TP
\fB\-f\fR
Force existing DUMPFILE to be overwritten and mem-usage to work with older
kernel as well.
.br
.B Example:
.br
# makedumpfile \-f \-d 31 \-x vmlinux /proc/vmcore dumpfile
.br
This command overwrites \fIDUMPFILE\fR even if it already exists.
.br
# makedumpfile \-f \-\-mem\-usage /proc/kcore
.br
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.

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

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

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

.TP
\fB\-\-config\fR \fIFILTERCONFIGFILE\fR
Used in conjunction with \-x \fIVMLINUX\fR option, to specify the filter
config file \fIFILTERCONFIGFILE\fR that contains erase commands to filter out
desired kernel data from vmcore while creating \fIDUMPFILE\fR. For filter
command syntax please refer to \fBmakedumpfile.conf(5)\fR.

.TP
\fB\-\-eppic\fR \fIEPPICMACRO\fR
Used in conjunction with \-x \fIVMLINUX\fR 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 \fIDUMPFILE\fR.
When directory is specified, all the eppic macros in the directory are processed.

.TP
\fB\-F\fR
Output the dump data in the flattened format to the standard output for
transporting the dump data by SSH.
.br
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 \fIDUMPFILE\fR (readable with analysis tools)
by \-R option. By which option is specified with \-F option, the format of the
rearranged \fIDUMPFILE\fR is fixed.
In other words, it is impossible to specify the \fIDUMPFILE\fR format when the
dump data is rearranged with \-R option. If specifying \-E option with \-F option,
the format of the rearranged \fIDUMPFILE\fR 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.
.br
.B Example:
.br
# makedumpfile \-F \-c \-d 31 \-x vmlinux /proc/vmcore \e
.br
| ssh user@host "cat > dumpfile.tmp"
.br
# makedumpfile \-F \-c \-d 31 \-x vmlinux /proc/vmcore \e
.br
| ssh user@host "makedumpfile \-R dumpfile"
.br
# makedumpfile \-F \-E \-d 31 \-i vmcoreinfo  /proc/vmcore \e
.br
| ssh user@host "makedumpfile \-R dumpfile"
.br
# makedumpfile \-F \-E \-\-xen-vmcoreinfo \fIVMCOREINFO\fR /proc/vmcore \e
.br
| ssh user@host "makedumpfile \-R dumpfile"

.TP
\fB\-R\fR
Rearrange the dump data in the flattened format from the standard input to a
normal \fIDUMPFILE\fR (readable with analysis tools).
.br
.B Example:
.br
# makedumpfile \-R dumpfile < dumpfile.tmp
.br
# makedumpfile \-F \-d 31 \-x vmlinux /proc/vmcore \e
.br
| 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 \fIDUMPFILE\fR, 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 \fIDUMPFILE\fR on a remote
host by running this script.
.br
.B Example:
.br
# makedumpfile \-F \-d 31 \-x vmlinux /proc/vmcore \e
.br
| ssh user@host "makedumpfile\-R.pl dumpfile"

.TP
\fB\-\-split\fR
Split the dump data to multiple \fIDUMPFILE\fRs in parallel. If specifying
\fIDUMPFILE\fRs 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 \fIDUMPFILE\fR is smaller than the system memory size which
is divided by the number of \fIDUMPFILE\fRs. This feature supports only
the kdump\-compressed format.
.br
.B Example:
.br
# makedumpfile \-\-split \-d 31 \-x vmlinux /proc/vmcore dumpfile1 dumpfile2

.TP
\fB\-\-num\-threads\fR \fITHREADNUM\fR
Using multiple threads to read and compress data of each page in parallel.
And it will reduces time for saving \fIDUMPFILE\fR.
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 \fIDUMPFILE\fR in kdump\-comressed
format from \fIVMCORE\fR in kdump\-compressed format or elf format.
.br
.B Example:
.br
# makedumpfile \-d 31 \-\-num\-threads 4 /proc/vmcore dumpfile

.TP
\fB\-\-reassemble\fR
Reassemble multiple \fIDUMPFILE\fRs, which are created by \-\-split option,
into one \fIDUMPFILE\fR. dumpfile1 and dumpfile2 are reassembled into dumpfile
on the following example.
.br
.B Example:
.br
# makedumpfile \-\-reassemble dumpfile1 dumpfile2 dumpfile

.TP
\fB\-b\fR \fI<order>\fR
Cache 2^order pages in ram when generating \fIDUMPFILE\fR before writing to output.
The default value is 4.

.TP
\fB\-\-cyclic\-buffer\fR \fIbuffer_size\fR
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 / (\fIbuffer_size\fR * 1024 * bit_per_bytes * page_size )

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

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

.TP
\fB\-\-splitblock\-size\fR \fIsplitblock_size\fR
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.
.br
.B Example:
.br
# makedumpfile \-\-splitblock\-size 1024 \-d 31 \-x vmlinux \-\-split /proc/vmcore dumpfile1 dumpfile2

.TP

\fB\-\-work\-dir\fR
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.

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

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

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

.TP
\fB\-\-xen-vmcoreinfo\fR \fIVMCOREINFO\fR
Specify \fIVMCOREINFO\fR instead of \fIXEN-SYMS\fR for analyzing the xen's memory usage.
.br
\fIVMCOREINFO\fR should be made beforehand by makedumpfile with \-g option, and
it contains the xen's information.
.br
.B Example:
.br
# makedumpfile \-E \-\-xen-vmcoreinfo \fIVMCOREINFO\fR /proc/vmcore dumpfile

.TP
\fB\-X\fR
Exclude all the user domain pages from Xen kdump's \fIVMCORE\fR, and extracts the
part of xen and domain-0. If \fIVMCORE\fR contains \fIVMCOREINFO\fR for Xen, it is
not necessary to specify \fI\-\-xen-syms\fR and \fI\-\-xen-vmcoreinfo\fR.
.br
.B Example:
.br
# makedumpfile \-E \-X /proc/vmcore dumpfile

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

.br
.B Example:
.br
# makedumpfile \-E \-X \-\-xen_phys_start 0xcee00000 /proc/vmcore dumpfile

.TP
\fB\-\-message-level\fR \fImessage_level\fR
Specify the message types.
.br
Users can restrict outputs printed by specifying \fImessage_level\fR
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
\fImessage_level\fR means progress indicator, common message, and error
message are printed, and this is a default value. Note that the maximum
value of \fImessage_level\fR is 31.
.br

 message | progress | common  | error   | debug   | report
 level   | indicator| message | message | message | message
.br
\-\-\-\-\-\-\-\-\-+\-\-\-\-\-\-\-\-\-\-+\-\-\-\-\-\-\-\-\-+\-\-\-\-\-\-\-\-\-+\-\-\-\-\-\-\-\-\-+\-\-\-\-\-\-\-\-\-
       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

.TP
\fB\-\-vtop\fR \fIvirtual_address\fR
This option is useful, when user debugs the translation problem
of virtual address. If specifing \fIvirtual_address\fR, 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.

.TP
\fB\-\-dump-dmesg\fR
This option overrides the normal behavior of makedumpfile.  Instead of
compressing and filtering a \fIVMCORE\fR to make it smaller, it simply
extracts the dmesg log from a \fIVMCORE\fR and writes it to the specified
\fILOGFILE\fR. If a \fIVMCORE\fR does not contain \fIVMCOREINFO\fR for dmesg,
it is necessary to specfiy [\-x \fIVMLINUX\fR] or [\-i \fIVMCOREINFO\fR].

.br
.B Example:
.br
# makedumpfile \-\-dump-dmesg /proc/vmcore dmesgfile
.br
# makedumpfile \-\-dump-dmesg -x vmlinux /proc/vmcore dmesgfile
.br


.TP
\fB\-\-partial-dmesg\fR
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.


.TP
\fB\-\-mem-usage\fR
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.

.br
.B Example:
.br
# makedumpfile \-\-mem-usage /proc/kcore
.br


.TP
\fB\-\-diskset=VMCORE\fR
Specify multiple \fIVMCORE\fRs created on sadump diskset configuration
the same number of times as the number of \fIVMCORE\fRs in increasing
order from left to right.  \fIVMCORE\fRs are assembled into a single
\fIDUMPFILE.

.br
.B Example:
.br
# makedumpfile \-x vmlinux \-\-diskset=vmcore1 \-\-diskset=vmcore2 dumpfile

.TP
\fB\-D\fR
Print debugging message.

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

.TP
\fB\-v\fR
Show the version of makedumpfile.

.SH ENVIRONMENT VARIABLES

.TP 8
.B 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.

.SH DIAGNOSTICS
makedumpfile exits with the following value.
.TP
\fB0\fR : makedumpfile succeeded.
.TP
\fB1\fR : makedumpfile failed without the following reasons.
.TP
\fB2\fR : makedumpfile failed due to the different version between  \fIVMLINUX\fR and \fIVMCORE\fR.

.SH AUTHORS
.PP
Written by Masaki Tachibana, and Ken'ichi Ohmichi.

.SH SEE ALSO
.PP
crash(8), gdb(1), kexec(8), makedumpfile.conf(5)