coredumpctl
Retrieve and process saved core dumps and metadata.
TLDR
List all captured core dumps
List captured core dumps for a program
Show information about the core dumps matching a program with PID
Invoke debugger using the last core dump of a program
Extract the last core dump of a program to a file
SYNOPSIS
coredumpctl [OPTIONS...] {COMMAND} [PID|COMM|EXE|MATCH...]
DESCRIPTION
coredumpctl is a tool that can be used to retrieve and process core dumps and metadata which were saved by systemd-coredump(8).
COMMANDS
The following commands are understood:
list
List core dumps captured in the journal matching specified characteristics. If no command is specified, this is the implied default.
The output is designed to be human readable and contains a table with the following columns:
TIME
The timestamp of the crash, as reported by the kernel.
PID
The identifier of the process that crashed.
UID, GID
The user and group identifiers of the process that crashed.
SIGNAL
The signal that caused the process to crash, when applicable.
COREFILE
Information whether the coredump was stored, and whether it is still accessible: "none" means the core was not stored, "-" means that it was not available (for example because the process was not terminated by a signal), "present" means that the core file is accessible by the current user, "journal" means that the core was stored in the "journal", "truncated" is the same as one of the previous two, but the core was too large and was not stored in its entirety, "error" means that the core file cannot be accessed, most likely because of insufficient permissions, and "missing" means that the core was stored in a file, but this file has since been removed.
EXE
The full path to the executable. For backtraces of scripts this is the name of the interpreter.
Its worth noting that different restrictions apply to data saved in the journal and core dump files saved in /var/lib/systemd/coredump, see overview in systemd-coredump(8). Thus it may very well happen that a particular core dump is still listed in the journal while its corresponding core dump file has already been removed.
info
Show detailed information about the last core dump or core dumps matching specified characteristics captured in the journal.
dump
Extract the last core dump matching specified characteristics. The core dump will be written on standard output, unless an output file is specified with --output=.
debug
Invoke a debugger on the last core dump matching specified characteristics. By default, gdb(1) will be used. This may be changed using the --debugger= option or the $SYSTEMD_DEBUGGER environment variable. Use the --debugger-arguments= option to pass extra command line arguments to the debugger.
OPTIONS
The following options are understood:
-h, --help
Print a short help text and exit.
--version
Print a short version string and exit.
--no-pager
Do not pipe output into a pager.
--no-legend
Do not print the legend, i.e. column headers and the footer with hints.
--json=MODE
Shows output formatted as JSON. Expects one of "short" (for the shortest possible output without any redundant whitespace or line breaks), "pretty" (for a pretty version of the same, with indentation and line breaks) or "off" (to turn off JSON output, the default).
-1
Show information of the most recent core dump only, instead of listing all known core dumps. Equivalent to --reverse -n 1.
-n INT
Show at most the specified number of entries. The specified parameter must be an integer greater or equal to 1.
-S, --since
Only print entries which are since the specified date.
-U, --until
Only print entries which are until the specified date.
-r, --reverse
Reverse output so that the newest entries are displayed first.
-F FIELD, --field=FIELD
Print all possible data values the specified field takes in matching core dump entries of the journal.
-o FILE, --output=FILE
Write the core to FILE.
--debugger=DEBUGGER
Use the given debugger for the debug command. If not given and $SYSTEMD_DEBUGGER is unset, then gdb(1) will be used.
-A ARGS, --debugger-arguments=ARGS
Pass the given ARGS as extra command line arguments to the debugger. Quote as appropriate when ARGS contain whitespace. (See Examples.)
--file=GLOB
Takes a file glob as an argument. If specified, coredumpctl will operate on the specified journal files matching GLOB instead of the default runtime and system journal paths. May be specified multiple times, in which case files will be suitably interleaved.
-D DIR, --directory=DIR
Use the journal files in the specified DIR.
-q, --quiet
Suppresses informational messages about lack of access to journal files and possible in-flight coredumps.
--all
Look at all available journal files in /var/log/journal/ (excluding journal namespaces) instead of only local ones.
MATCHING
A match can be:
PID
Process ID of the process that dumped core. An integer.
COMM
Name of the executable (matches COREDUMP_COMM=). Must not contain slashes.
EXE
Path to the executable (matches COREDUMP_EXE=). Must contain at least one slash.
MATCH
General journalctl match filter, must contain an equals sign ("="). See journalctl(1).
EXIT STATUS
On success, 0 is returned; otherwise, a non-zero failure code is returned. Not finding any matching core dumps is treated as failure.
ENVIRONMENT
$SYSTEMD_DEBUGGER
Use the given debugger for the debug command. See the --debugger= option.
EXAMPLES
Example 1. List all the core dumps of a program
$ coredumpctl list /usr/lib64/firefox/firefox TIME PID UID GID SIG COREFILE EXE SIZE Tue ... 8018 1000 1000 SIGSEGV missing /usr/lib64/firefox/firefox n/a Wed ... 251609 1000 1000 SIGTRAP missing /usr/lib64/firefox/firefox n/a Fri ... 552351 1000 1000 SIGSEGV present /usr/lib64/firefox/firefox 28.7M
The journal has three entries pertaining to /usr/lib64/firefox/firefox, and only the last entry still has an available core file (in external storage on disk).
Note that coredumpctl needs access to the journal files to retrieve the relevant entries from the journal. Thus, an unprivileged user will normally only see information about crashing programs of this user.
Example 2. Invoke gdb on the last core dump
$ coredumpctl debug
Example 3. Use gdb to display full register info from the last core dump
$ coredumpctl debug --debugger-arguments="-batch -ex info all-registers"
Example 4. Show information about a core dump matched by PID
$ coredumpctl info 6654 PID: 6654 (bash) UID: 1000 (user) GID: 1000 (user) Signal: 11 (SEGV) Timestamp: Mon 2021-01-01 00:00:01 CET (20s ago) Command Line: bash -c $kill -SEGV $$ Executable: /usr/bin/bash Control Group: /user.slice/user-1000.slice/... Unit: user@1000.service User Unit: vte-spawn-....scope Slice: user-1000.slice Owner UID: 1000 (user) Boot ID: ... Machine ID: ... Hostname: ... Storage: /var/lib/systemd/coredump/core.bash.1000.....zst (present) Disk Size: 51.7K Message: Process 130414 (bash) of user 1000 dumped core. Stack trace of thread 130414: #0 0x00007f398142358b kill (libc.so.6 + 0x3d58b) #1 0x0000558c2c7fda09 kill_builtin (bash + 0xb1a09) #2 0x0000558c2c79dc59 execute_builtin.lto_priv.0 (bash + 0x51c59) #3 0x0000558c2c79709c execute_simple_command (bash + 0x4b09c) #4 0x0000558c2c798408 execute_command_internal (bash + 0x4c408) #5 0x0000558c2c7f6bdc parse_and_execute (bash + 0xaabdc) #6 0x0000558c2c85415c run_one_command.isra.0 (bash + 0x10815c) #7 0x0000558c2c77d040 main (bash + 0x31040) #8 0x00007f398140db75 __libc_start_main (libc.so.6 + 0x27b75) #9 0x0000558c2c77dd1e _start (bash + 0x31d1e)
Example 5. Extract the last core dump of /usr/bin/bar to a file named bar.coredump
$ coredumpctl -o bar.coredump dump /usr/bin/bar
SEE ALSO
systemd-coredump(8), coredump.conf(5), systemd-journald.service(8), gdb(1)
