Description

Core dumps are generated by the `login` and `getty` processes under the FPC, but there are no FPC reboots. The following core dumps have been observed:

Symptoms

root@re0-<Host name>> show system core-dumps no-forwarding

-rw-r--r-- 1 root wheel   51551 Apr 3 22:42 /var/crash/core-re0-<Host name>-fpc3-agetty.94.tgz
-rw-r--r-- 1 root wheel   70631 Apr 3 22:47 /var/crash/core-re0-<Host name>-fpc3-login.shadow.95.tgz
-rw-r--r-- 1 root wheel   108148 Apr 3 22:48 /var/crash/core-re0-<Host name>-fpc3-login.shadow.96.tgz
-rw-r--r-- 1 root wheel   94022 Apr 3 23:42 /var/crash/core-re0-<Host name>-fpc3-login.shadow.97.tgz
-rw-r--r-- 1 root wheel   57709 Apr 3 23:47 /var/crash/core-re0-<Host name>-fpc3-login.shadow.98.tgz

 

Solution

Workaround:

1. Identify the Cause:
   - The core dumps are generated by the `login` and `getty` processes under the FPC due to electrical noise on the internal console port (CTY) of the FPC.
   - This is a known hardware limitation and is generally harmless.

2. Impact Assessment:
   - The issue is typically due to electrical noise on the UART line (CTY), which sends a `SIGQUIT` signal to the `login`/`getty` process, causing it to crash.
   - Since this occurs on the console port (CTY) and not on the active service ports, there is no impact on the services running on the FPC.

3. Recovery:
   - The issue will be resolved immediately after the login/getty process is reset.
   - If no further noise is reported, this issue is not expected to cause service disruption.

4. Logs Review:
   - During the time of the issue, you may observe logs such as:
     getty[818]: checkname failed: Operation not permitted
     
5. Further Actions:
   - If the core dumps are observed repeatedly and are affecting operations, consider replacing the FPC.

Modification History

2024-09-12 : Article Created