KDUMP(1) - General Commands Manual #
KDUMP(1) - General Commands Manual
NAME #
kdump - display kernel trace data
SYNOPSIS #
kdump [-dHlnRTXx] [-f file] [-m maxdata] [-P program] [-p pid] [-t trstr] [-u label]
DESCRIPTION #
kdump displays the kernel trace files produced with ktrace(1) in human-readable format. By default, the file ktrace.out in the current directory is displayed, unless overridden by the -f option.
The options are as follows:
-d
Display all numbers in decimal. By default, values are printed out in hexadecimal.
-f file
Display the specified file instead of ktrace.out. Specifying ‘-’ will read from standard input.
-H
Display thread identifiers.
-l
Loop reading the trace file, once the end-of-file is reached, waiting for more data.
-m maxdata
Display at most maxdata bytes when decoding I/O.
-n
Suppress ad hoc translations. Normally kdump tries to decode many system calls into a more human-readable format. For example, ioctl(2) values are replaced with the macro name and errno values are replaced with the strerror(3) string. Suppressing this feature yields a more consistent output format and is easily amenable to further processing.
-P program
Show output only for processes with program as their command name.
-p pid
Show output only for the pid specified.
-R
Display relative timestamps (time since previous entry).
-T
Display absolute timestamps for each entry (seconds since the Epoch).
-TR
If both options are specified, display timestamps relative to trace start.
-t trstr
Select which tracepoints to display. The argument can contain one or more of the following letters. By default all trace points except for X are enabled.
c
trace system calls
i
trace I/O
n
trace namei translations
p
trace violation of pledge(2) restrictions
s
trace signal processing
S
trace violation of pinsyscalls(2)
t
trace various structures
u
trace user data coming from utrace(2)
x
trace argument vector in execve(2)
X
trace environment in execve(2)
+
trace the default points
-u label
Display utrace(2) tracepoints having utrace(2) label label as strings with vis(3) escaping, without ktrace(2) header information.
-X
Display I/O data with hexadecimal data and printable ASCII characters side by side.
-x
Display I/O data in hexadecimal.
The -t and -u options are mutually exclusive; the last one specified overrides any previous ones.
FILES #
ktrace.out
default ktrace dump file
SEE ALSO #
HISTORY #
The kdump command appeared in 4.3BSD-Reno.
OpenBSD 7.5 - December 15, 2023