---
name: "mcelog.triggers"
section: "5"
platform: "linux"
package: "mcelog"
version: "147+dfsg-1"
release: "Debian 9 (Stretch)"
platforms: ["linux"]
url: "https://new.carta.tech/mcelog.triggers"
---

# mcelog.triggers(5)

mcelog trigger scripts reference

## NAME

mcelog.triggers - mcelog trigger scripts reference

## SYNOPSIS

**/etc/mcelog/bus-error-trigger**\
 **/etc/mcelog/cache-error-trigger**\
 **/etc/mcelog/dimm-error-trigger**\
 **/etc/mcelog/iomca-error-trigger**\
 **/etc/mcelog/page-error-trigger**\
 **/etc/mcelog/socket-memory-error-trigger**\
 **/etc/mcelog/unknown-error-trigger**\

## DESCRIPTION

**[mcelog(8)](/mcelog/8.md)** maintains thresholds of errors using a  *leaky-bucket* algorithm. When the number of errors in a specific time window exceeds a pre-configured threshold a  *trigger* will be executed. Triggers are usually shell scripts in the **/etc/mcelog** directory but can be also other internal actions. Thresholds and triggers can be configured in **[mcelog.conf(5)](/mcelog.conf/5.md)**

Trigger will run as the user configured for mcelog in  *mcelog.conf,* by default root. The default trigger action can be overridden by specifying a different trigger script in the configuration file. Actions in addition to the default trigger (like notifying an administrator) can be put into the respective */etc/mcelog/\*.local* script which is executed after the default action. This allows updating the default scripts without overriding local actions. All trigger actions are also logged to syslog.

**The DIMM and socket memory error triggers**

The  **/etc/mcelog/dimm-error-trigger** and  **/etc/mcelog/socket-memory-error-trigger** scripts are executed when a DIMM or a CPU socket exceeds a configured corrected or uncorrected memory error threshold. The thresholds are configured in the  **mcelog.conf** *\[dimm\]* and *\[socket\]* sections. The default triggers log a warning message in the system log. The triggers are only executed when mcelog runs as a daemon.

Arguments are passed as environment variables

| | |
| --- | --- |
| THRESHOLD | human readable threshold status |
| MESSAGE | Human readable consolidated error message |
| TOTALCOUNT | total corrected or uncorrected count of errors for current DIMM depending on what triggered the event |
| LOCATION | Consolidated location as a single string |
| DMI\_LOCATION | DIMM location from DMI/SMBIOS if available |
| DMI\_NAME | DIMM identifier from DMI/SMBIOS if available |
| DIMM | DIMM number reported by hardware |
| CHANNEL | Channel number reported by hardware |
| SOCKETID | Socket ID of CPU that includes the memory controller with the DIMM |
| CECOUNT | Total corrected error count for DIMM |
| UCCOUNT | Total uncorrected error count for DIMM |
| LASTEVENT | Time stamp of event that triggered threshold (in time\_t format, seconds) |
| THRESHOLD\_COUNT | Total umber of events in current threshold time period of specific type |

After the default action local actions in  **/etc/mcelog/dimm-error-trigger.local** or respective  **/etc/mcelog/socket-memory-error-trigger.local** are executed.

**The page error trigger**

The  **/etc/mcelog/page-error-trigger** script is  executed by mcelog in daemon mode when a page in memory exceeds a pre-configured corrected or uncorrected error threshold. mcelog internally also implements offlining the page through the kernel. This is configured through the  *\[page\]* section of  **[mcelog.conf(5)](/mcelog.conf/5.md)**

The environment arguments are the same as for the  *dimm-error-trigger* script

After the default action local actions in  */etc/mcelog/page-error-trigger.loccal are executed.*

**The cache error trigger**

The */etc/mcelog/cache-error-trigger* shell script is called for cache error handling in daemon mode when a CPU reports excessive corrected cache errors. This could be a indication for future uncorrected errors.

This trigger is configured through the  **\[cache\]** section in the  **[mcelog.conf(5)](/mcelog.conf/5.md)** configuration file. The threshold is defined by the CPU.  The default trigger offlines the affected CPU cores, unless it is the last core running.

Arguments are passed as environment variables

| | |
| --- | --- |
| MESSAGE | Human readable error message |
| CPU | Linux CPU number that triggered the error |
| LEVEL | Cache level affected by error |
| TYPE | Cache type affected by error (Data,Instruction,Generic) |
| AFFECTED\_CPUS | List of CPUs sharing the affected cache |
| SOCKETID | Socket ID of affected CPU |

After the default action local actions in  */etc/mcelog/cache-error-trigger.local are executed.*

**The bus-uc-threshold-trigger**

The  **bus-uc-threshold-trigger** runs on uncorrected errors on a IO bus. It is configured through the  **bus-uc-threshold-trigger** and **bus-uc-threshold-trigger-threshold** options in */etc/[mcelog.conf(5)](/mcelog.conf/5.md).* By default it logs a message with the error location to the system log. After the default action local actions in  */etc/mcelog/bus-uc-error-trigger.local* are executed.

Arguments are passed as environment variables

| | |
| --- | --- |
| MESSAGE | Human readable consolidated error message. |
| LOCATION | Consolidated location as a single string |
| SOCKETID | Socket ID of CPU that includes the memory controller with the DIMM |
| LEVEL | Interconnect level |
| PARTICIPATION | Processor Participation (Originator, Responder or Observer) |
| REQUEST | Request type (read, write, prefetch, etc.) |
| ORIGIN | Memory or IO |
| TIMEOUT | The request timed out or not |

**The iomca-error-trigger**

The  **iomca-error-trigger** runs when a socket receives bus or interconnect errors. It is configured through the  **iomca-error-trigger** and  **iomca-error-trigger-threshold** options in */etc/mcelog.conf. By default it logs a message with the error location to the system log.* After the default action local actions in  */etc/mcelog/iomca-error-trigger.local are executed.*

Arguments are passed as environment variables

| | |
| --- | --- |
| MESSAGE | Human readable consolidated error message |
| LOCATION | Consolidated location as a single string |
| SOCKETID | Socket ID of CPU that includes the memory controller with the DIMM |
| CPU | Linux CPU number that triggered the error |
| SET | PCI segment number |
| BUS | PCI bus number |
| DEVICE | PCI device number |
| FUNCTION | PCI function number |

**The unknown-error-trigger**

The  **unknown-error-trigger** runs on any errors not otherwise categorized. It is configured through the  **unknown-error-trigger** and **unknown-error-trigger-threshold** options in */etc/mcelog.conf.* By default it logs a message to the system log. After the default action local actions in  */etc/mcelog/unknown-error-trigger.local* are executed.

Arguments are passed as environment variables

| | |
| --- | --- |
| MESSAGE | Human readable consolidated error message |
| LOCATION | Consolidated location as a single string |
| SOCKETID | Socket ID of CPU that includes the memory controller with the DIMM |
| CPU | Linux CPU number that triggered the error |
| STATUS | IA32\_MCi\_STATUS register value |
| ADDR | IA32\_MCi\_ADDR register value |
| MISC | IA32\_MCi\_MISC register value |
| MCGSTATUS | IA32\_MCG\_STATUS register value |
| MCGCAP | IA32\_MCG\_CAP register value |

## SEE ALSO

http://www.mcelog.org

**[mcelog(8)](/mcelog/8.md),** **[mcelog.conf(5)](/mcelog.conf/5.md)**