Controller & Vpoiske
Controller Controller
Vpoiske Vpoiske
Controller Controller
Hey, have you ever thought about how a server’s log is like a confession, telling us every little thing that happened before an incident? Maybe we could dig into one of those logs and see if it reveals anything unexpected.
Vpoiske Vpoiske
Sounds like a solid lead—logs are the most honest witness you can get. Give me the server type, the timeframe, and the incident you’re chasing. Then I can tell you what lines might be the confession.
Controller Controller
Server type: Linux RHEL 8 running a custom web service. Timeframe: 2 pm to 4 pm UTC on the 12th of last month. Incident: a sudden spike in CPU usage followed by a graceful shutdown of the web process.
Vpoiske Vpoiske
Let’s hunt the clues in /var/log/messages and /var/log/syslog for that window. Look for any “CPU usage” spikes or “coredump” entries, check the Apache or nginx logs for a sudden “worker killed” or “timeout” message, and then dig into the custom service’s own logs for a “shutdown” or “panic” call. Cross‑reference the timestamps—if the spike and the shutdown line up, the culprit’s probably in the service’s code or a misbehaving dependency. Once you spot the exact log entry, you’ll have the confession you’re after.
Controller Controller
Got it. I’ll pull the logs for that window, flag the CPU spikes, core dumps, and worker exits, then match them to the service shutdown entry. If the timestamps align, the culprit will be clear.Done.Done.
Vpoiske Vpoiske
Nice work. Now sift through the flagged lines—look for anything that looks like a forced kill or an exception. If you spot a stack trace or a suspicious “segfault” around the same moment, that’s your smoking gun. If it’s just a clean shutdown, we’ll need to dig deeper into the process’ health checks. Let me know what you find, and we’ll keep chasing that truth.
Controller Controller
Found a segfault at 2:18:17 UTC. The stack trace shows a null pointer dereference in the custom service’s worker thread, followed by a SIGSEGV and a coredump. The web server log shows the worker killed at the same second. That’s the smoking gun. The service’s shutdown routine was invoked immediately after. Next step is to review the code around that dereference and tighten the null checks.
Vpoiske Vpoiske
Great, that’s the confession we were after. Grab the source for the worker thread that’s blowing up—especially the pointer that’s ending up null at 2:18:17. Check the surrounding logic: who’s allocating it, who’s passing it in, and what the null‑check guard looks like. If you can isolate the line, you can patch the bug or add a defensive guard. Let me know what you see, and we’ll tighten it up.