lttng-untrack(1)
================


NAME
----
lttng-untrack - Remove one or more property values from an LTTng process tracker


SYNOPSIS
--------
[verse]
Untrack processes for Linux kernel channels:

[verse]
*lttng* ['linkgenoptions:(GENERAL OPTIONS)'] *untrack* option:--kernel [option:--session='SESSION']
      [option:--pid='PID'[,'PID']... | option:--pid option:--all]
      [option:--vpid='PID'[,'PID']... | option:--vpid option:--all]
      [option:--uid='USER'[,'USER']... | option:--uid option:--all]
      [option:--vuid='USER'[,'USER']... | option:--vuid option:--all]
      [option:--gid='GROUP'[,'GROUP']... | option:--gid option:--all]
      [option:--vgid='GROUP'[,'GROUP']... | option:--vgid option:--all]

Untrack processes for user space channels:

[verse]
*lttng* ['linkgenoptions:(GENERAL OPTIONS)'] *untrack* option:--userspace [option:--session='SESSION']
      [option:--vpid='PID'[,'PID']... | option:--vpid option:--all]
      [option:--vuid='USER'[,'USER']... | option:--vuid option:--all]
      [option:--vgid='GROUP'[,'GROUP']... | option:--vgid option:--all]


DESCRIPTION
-----------
The `lttng untrack` commands removes one or more property values from an
LTTng process tracker.

See man:lttng-track(1) to learn more about LTTng process trackers.

The `lttng untrack` command removes specific property values from a
process tracker's whitelist. The property values to remove must have
been precedently added by man:lttng-track(1). It is also possible to
remove all the values of a given property from the whitelist with the
option:--all option following the specific property option.

The available process properties are:

option:--pid::
    Process ID as seen by the Linux kernel (root namespace).

option:--uid::
    User ID or name as seen by the Linux kernel (root namespace).

option:--gid::
    Group ID or name as seen by the Linux kernel (root namespace).

option:--vpid::
    Process ID as seen by the traced process.

option:--vuid::
    User ID or name as seen by the traced process.

option:--vgid::
    Group ID or name as seen by the traced process.


Understanding the whitelist
~~~~~~~~~~~~~~~~~~~~~~~~~~~
One common operation is to create a tracing session (see
man:lttng-create(1)), remove all the process ID property values from the
process tracker whitelist, start tracing, and then manually track
processes with a given PID while tracing is active.

Assume the maximum system PID is 7 for this example.

Command:

[role="term"]
----
$ lttng create
----

Initial whitelist:

-------------------------------
[0] [1] [2] [3] [4] [5] [6] [7]
-------------------------------

Command:

[role="term"]
----
$ lttng untrack --kernel --pid --all
----

Whitelist:

-------------------------------
[ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ]
-------------------------------

Commands:

[role="term"]
----
$ lttng enable-event --kernel ...
$ lttng start
$ # ...
$ lttng track --kernel --pid=3,5
----

Whitelist:

-------------------------------
[ ] [ ] [ ] [3] [ ] [5] [ ] [ ]
-------------------------------

Command:

[role="term"]
----
$ lttng track --kernel --pid=2
----

Whitelist:

-------------------------------
[ ] [ ] [2] [3] [ ] [5] [ ] [ ]
-------------------------------


include::common-cmd-options-head.txt[]


Domain
~~~~~~
One of:

option:-k, option:--kernel::
    Untrack processes for Linux kernel channels.

option:-u, option:--userspace::
    Untrack processes for user space channels.


Target
~~~~~~
option:-s, option:--session='SESSION'::
    Untrack processes in the tracing session named 'SESSION' instead of
    the current tracing session.


Process property
~~~~~~~~~~~~~~~~
option:-a, option:--all::
    Following any of the property options below (without an option's
    argument): remove _all_ possible values of this property from the
    process tracker's whitelist.

option:--pid[='PID'[,'PID']...]::
    Remove process ID 'PID', as seen by the Linux kernel (root
    namespace), from the tracker's whitelist.

option:--uid[='USER'[,'USER']...]::
    Remove user ID or name 'USER', as seen by the Linux kernel (root
    namespace), from the tracker's whitelist.

option:--gid[='GROUP'[,'GROUP']...]::
    Remove group ID or name 'GROUP', as seen by the Linux kernel (root
    namespace), from the tracker's whitelist.

option:--vpid[='PID'[,'PID']...]::
    Remove process ID 'VPID', as seen by the traced process, from the
    tracker's whitelist.

option:--vuid[='USER'[,'USER']...]::
    Remove user ID or name 'USER', as seen by the traced process, from
    the tracker's whitelist.

option:--vgid[='GROUP'[,'GROUP']...]::
    Remove group ID or name 'GROUP', as seen by the traced process, from
    the tracker's whitelist.


include::common-cmd-help-options.txt[]


include::common-cmd-footer.txt[]


SEE ALSO
--------
man:lttng-track(1),
man:lttng(1)