lttng-crash(1) (v2.12)


lttng-crash — Recover and view LTTng 2 trace buffers in the event of a crash


lttng-crash [--extract=PATH | --viewer=VIEWER] [-v | -vv | -vvv] SHMDIR


The Linux Trace Toolkit: next generation is an open source software package used for correlated tracing of the Linux kernel, user applications, and user libraries.

LTTng consists of Linux kernel modules (for Linux kernel tracing) and dynamically loaded libraries (for user application and library tracing).

The lttng-crash command-line tool is used to recover and view LTTng trace buffers in the event of a system crash.

lttng-crash reads files within the directory SHMDIR and does one of:

Without the --extract option

Launches a trace reader (see the --viewer option) to view the recovered traces.

With the --extract option

Extracts them as uncorrupted LTTng traces on the file system.

SHMDIR is the directory specified as the argument of the --shm-path option of the lttng-create(1) command used to create the tracing session for which to recover the traces.


-x PATH, --extract=PATH

Extract recovered traces to path PATH; do not execute the trace viewer.

-v, --verbose

Increase verbosity.

Three levels of verbosity are available, which are triggered by appending additional v letters to the option (that is, -vv and -vvv).

-e VIEWER, --viewer=VIEWER

Use trace viewer VIEWER to view the trace buffers. VIEWER is the absolute path to the viewer command to use, and it can contain command arguments as well. The trace directory paths are passed to the VIEWER command as its last arguments.

Without this option, lttng crash uses babeltrace2(1) if it’s available. Otherwise, it tries to use babeltrace(1).

Program information

-h, --help

Show help.

-V, --version

Show version.







Fatal error


If you encounter any issue or usability problem, please report it on the LTTng bug tracker.



This program is part of the LTTng-tools project.

LTTng-tools is distributed under the GNU General Public License version 2. See the LICENSE file for details.


Special thanks to Michel Dagenais and the DORSAL laboratory at École Polytechnique de Montréal for the LTTng journey.

Also thanks to the Ericsson teams working on tracing which helped us greatly with detailed bug reports and unusual test cases.