--- name: "lttng-untrack" section: "1" platform: "linux" package: "lttng-tools" version: "2.13.15-2" release: "Debian 13 (Trixie)" platforms: ["linux"] url: "https://new.carta.tech/lttng-untrack" --- # lttng-untrack(1) Disallow specific processes to record LTTng events ## NAME lttng-untrack - Disallow specific processes to record LTTng events ## SYNOPSIS Disallow specific processes to record Linux kernel events: ``` lttng [GENERAL OPTIONS] untrack --kernel [--session=SESSION] (--pid=PID[,PID]... | --vpid=VPID[,VPID]... | --uid=UID[,UID]... | --vuid=VUSER[,VUSER]... | --gid=GID[,GID]... | --vgid=VGROUP[,VGROUP]...)... ``` ``` lttng [GENERAL OPTIONS] untrack --kernel [--session=SESSION] --all (--pid | --vpid | --uid | --vuid | --gid | --vgid)... ``` Disallow specific processes to record user space events: ``` lttng [GENERAL OPTIONS] untrack --userspace [--session=SESSION] (--vpid=VPID[,VPID]... | --vuid=VUSER[,VUSER]... | --vgid=VGROUP[,VGROUP]...)... ``` ``` lttng [GENERAL OPTIONS] untrack --userspace [--session=SESSION] --all (--vpid | --vgid | --vuid)... ``` ## DESCRIPTION The **lttng untrack** command disallows one or more processes to record LTTng events based on their attributes within: With the **--session**=*SESSION* option The recording session named *SESSION*. Without the **--session** option The current recording session (see [**lttng-concepts**(7)](/lttng-concepts/7.md) to learn more about the current recording session). See [**lttng-concepts**(7)](/lttng-concepts/7.md) to learn more about recording sessions and recording event rules. The **untrack** command removes values from *inclusion sets* of process attributes. See [**lttng-track**(1)](/lttng-track/1.md) to learn more about inclusion sets. See the “EXAMPLES” section below for usage examples. ### Inclusion set example A common operation is to create a recording session (see [**lttng-create**(1)](/lttng-create/1.md)), remove all the entries from the Linux kernel process ID inclusion set, start recording, and then manually add PIDs while the recording session is active. Assume the maximum system PID is 7 for this example. 1\. Command: ``` $ lttng create ``` Initial inclusion set: ``` [0] [1] [2] [3] [4] [5] [6] [7] ``` 2\. Command: ``` $ lttng untrack --kernel --all --pid ``` Inclusion set: ``` [ ] [ ] [ ] [ ] [ ] [ ] [ ] [ ] ``` 3\. Commands: ``` $ lttng enable-event --kernel ... $ lttng start $ # ... $ lttng track --kernel --pid=3,5 ``` Inclusion set: ``` [ ] [ ] [ ] [3] [ ] [5] [ ] [ ] ``` 4\. Command: ``` $ lttng track --kernel --pid=2 ``` Inclusion set: ``` [ ] [ ] [2] [3] [ ] [5] [ ] [ ] ``` ## OPTIONS See [**lttng**(1)](/lttng/1.md) for *GENERAL OPTIONS*. ### Tracing domain One of: - **-k**, **--kernel** Remove values from one or more Linux kernel inclusion sets. - **-u**, **--userspace** Remove values from one or more user space inclusion sets. ### Recording target - **-s** *SESSION*, **--session**=*SESSION* Remove values from one or more inclusion sets of the recording session named *SESSION* instead of the current recording session. ### Inclusion set selection **-p** \[*PID*\[,*PID*\]...\], **--pid**\[=*PID*\[,*PID*\]...\] For each *PID* argument, remove *PID* from the process ID inclusion set of the selected recording session and domain. *PID* is the process ID attribute of a process as seen from the root PID namespace (see [**pid\_namespaces**(7)](/pid_namespaces/7.md)). Only available with **--kernel** option. **--vpid**\[=*VPID*\[,*VPID*\]...\] For each *VPID* argument, remove *VPID* from the virtual process ID inclusion set of the selected recording session and domain. *VPID* is the virtual process ID attribute of a process as seen from the PID namespace of the process (see [**pid\_namespaces**(7)](/pid_namespaces/7.md)). **--uid**\[=*USER*\[,*USER*\]...\] For each *USER* argument, remove *USER* from the user ID inclusion set of the selected recording session and domain. *USER* is either: • The real user ID (see **getuid**(3)) of a process as seen from the root user namespace (see [**user\_namespaces**(7)](/user_namespaces/7.md)). • A user name. The connected LTTng session daemon (see [**lttng-sessiond**(8)](/lttng-sessiond/8.md)) performs the user name resolution on removal from the user ID inclusion set. Only available with **--kernel** option. **--vuid**\[=*VUSER*\[,*VUSER*\]...\] For each *VUSER* argument, remove *VUSER* from the virtual user ID inclusion set of the selected recording session and domain. *VUSER* is either: • The real user ID (see **getuid**(3)) of a process as seen from the user namespace (see [**user\_namespaces**(7)](/user_namespaces/7.md)). • A user name. The connected LTTng session daemon (see [**lttng-sessiond**(8)](/lttng-sessiond/8.md)) performs the user name resolution on removal from the virtual user ID inclusion set. **--gid**\[=*GROUP*\[,*GROUP*\]...\] For each *GROUP* argument, remove *GROUP* from the group ID inclusion set of the selected recording session and domain. *GROUP* is either: • The real group ID (see **getgid**(3)) of a process as seen from the root user namespace (see [**user\_namespaces**(7)](/user_namespaces/7.md)). • A group name. The connected LTTng session daemon (see [**lttng-sessiond**(8)](/lttng-sessiond/8.md)) performs the group name resolution on removal from the group ID inclusion set. Only available with **--kernel** option. **--vgid**\[=*VGROUP*\[,*VGROUP*\]...\] For each *VGROUP* argument, remove *VGROUP* from the virtual group ID inclusion set of the selected recording session and domain. *VGROUP* is either: • The real group ID (see **getgid**(3)) of a process as seen from the user namespace (see [**user\_namespaces**(7)](/user_namespaces/7.md)). • A group name. The connected LTTng session daemon (see [**lttng-sessiond**(8)](/lttng-sessiond/8.md)) performs the group name resolution on removal from the virtual group ID inclusion set. ### Inclusion set operation - **-a**, **--all** With one or more empty **--pid**, **--vpid**, **--uid**, **--vuid**, **--gid**, and **--vgid** options: clear the selected inclusion sets. ### Program information - **-h**, **--help** Show help. This option attempts to launch **/usr/bin/man** to view this manual page. Override the manual pager path with the **LTTNG\_MAN\_BIN\_PATH** environment variable. - **--list-options** List available command options and quit. ## EXIT STATUS **0** Success **1** Command error **2** Undefined command **3** Fatal error **4** Command warning (something went wrong during the command) ## ENVIRONMENT **LTTNG\_ABORT\_ON\_ERROR** Set to **1** to abort the process after the first error is encountered. **LTTNG\_HOME** Path to the LTTng home directory. Defaults to **$HOME**. Useful when the Unix user running the commands has a non-writable home directory. **LTTNG\_MAN\_BIN\_PATH** Absolute path to the manual pager to use to read the LTTng command-line help (with [**lttng-help**(1)](/lttng-help/1.md) or with the **--help** option) instead of **/usr/bin/man**. **LTTNG\_SESSION\_CONFIG\_XSD\_PATH** Path to the directory containing the **session.xsd** recording session configuration XML schema. **LTTNG\_SESSIOND\_PATH** Absolute path to the LTTng session daemon binary (see [**lttng-sessiond**(8)](/lttng-sessiond/8.md)) to spawn from the [**lttng-create**(1)](/lttng-create/1.md) command. The **--sessiond-path** general option overrides this environment variable. ## FILES **$LTTNG\_HOME/.lttngrc** Unix user’s LTTng runtime configuration. This is where LTTng stores the name of the Unix user’s current recording session between executions of [**lttng**(1)](/lttng/1.md). [**lttng-create**(1)](/lttng-create/1.md) and [**lttng-set-session**(1)](/lttng-set-session/1.md) set the current recording session. **$LTTNG\_HOME/lttng-traces** Default output directory of LTTng traces in local and snapshot modes. Override this path with the **--output** option of the [**lttng-create**(1)](/lttng-create/1.md) command. **$LTTNG\_HOME/.lttng** Unix user’s LTTng runtime and configuration directory. **$LTTNG\_HOME/.lttng/sessions** Default directory containing the Unix user’s saved recording session configurations (see [**lttng-save**(1)](/lttng-save/1.md) and [**lttng-load**(1)](/lttng-load/1.md)). **/etc/lttng/sessions** Directory containing the system-wide saved recording session configurations (see [**lttng-save**(1)](/lttng-save/1.md) and [**lttng-load**(1)](/lttng-load/1.md)). **Note**\ **$LTTNG\_HOME** defaults to the value of the **HOME** environment variable. ## EXAMPLES **Example 1. Remove the PIDs 1728 and 3775 from the Linux kernel process ID inclusion set of the current recording session.** See the **--pid** option. ``` $ lttng untrack --kernel --pid=1728,3775 ``` **Example 2. Remove the IDs of a specific groups from the user space virtual group ID inclusion set of a specific recording session.** See the **--vgid** and **--session** options. ``` $ lttng untrack --userspace --session=my-session \ --vgid=docker,mysql ``` **Example 3. Remove all the user IDs from the Linux kernel user ID inclusion set of the current recording session.** See the **--all** and **--uid** options. ``` $ lttng untrack --kernel --all --uid ``` ## RESOURCES • LTTng project website \ • LTTng documentation \ • LTTng bug tracker \ • Git repositories \ • GitHub organization \ • Continuous integration \ • Mailing list \ for support and development: **lttng-dev@lists.lttng.org** • IRC channel \: **#lttng** on **irc.oftc.net** ## COPYRIGHT 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. ## THANKS 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. ## SEE ALSO [**lttng**(1)](/lttng/1.md), [**lttng-track**(1)](/lttng-track/1.md), [**lttng-concepts**(7)](/lttng-concepts/7.md)