coredumpctl — Retrieve and process saved core dumps and metadata
coredumpctl [OPTIONS...] {COMMAND} [PID|COMM|EXE|MATCH...]
coredumpctl is a tool that can be used to retrieve and process core dumps and metadata which were saved by systemd-coredump(8).
The following commands are understood:
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:
The timestamp of the crash, as reported by the kernel.
The identifier of the process that crashed.
The user and group identifiers of the process that crashed.
The signal that caused the process to crash, when applicable.
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.
The full path to the executable. For backtraces of scripts this is the name of the interpreter.
It's 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.
Show detailed information about the last core dump or core dumps matching specified characteristics captured in the journal.
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=.
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.
The following options are understood:
-h, --help¶--version¶--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.
--root=ROOT¶Use root directory ROOT when searching for coredumps.
--image=image¶Takes a path to a disk image file or block device node. If specified, all operations
are applied to file system in the indicated disk image. This option is similar to
--root=, but operates on file systems stored in disk images or block devices. The
disk image should either contain just a file system or a set of file systems within a GPT partition
table, following the Discoverable Partitions
Specification. For further information on supported disk images, see
systemd-nspawn(1)'s
switch of the same name.
--image-policy=policy¶Takes an image policy string as argument, as per
systemd.image-policy(7). The
policy is enforced when operating on the disk image specified via --image=, see
above. If not specified defaults to the "*" policy, i.e. all recognized file systems
in the image are used.
-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.
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).
On success, 0 is returned; otherwise, a non-zero failure code is returned. Not finding any matching core dumps is treated as failure.
$SYSTEMD_DEBUGGER¶Use the given debugger for the debug
command. See the --debugger= option.
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 - Wed … 251609 1000 1000 SIGTRAP missing /usr/lib64/firefox/firefox - 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 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)
Size on Disk: 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