Please improve the error handling (catch possible coredumps)

[Photon89]

Hi guys,

yesterday I spent almost the whole day trying to figure out what caused a LightDM crash. The crash put the system into an unusable state (a loop of black screens with no TTY access). There are several components to it:

1. When LightDM crashes, it is not obvious that it is LightDM that is crashed. It could be a video driver problem as well.
2. When the system is not accessible, it is hard to track down the issue.
3. LightDM doesn't provide a useful error output, only a rather cryptic stack trace in the journal.

In my case, the original issue was that libpixbufloader-svg.so hasn't been found. Instead of dying, LightDM could

• Offer limited functionality (without fancy graphics) and/or
• Show some error message (graphically or at least in CLI output) which helps to find the issue

In the end I could only solve the issue by installing SDDM, logging into Xfce, seeing that other apps crash as well and finding meaningful error messages in their output.

Here is what was in the journal: https://pastebin.com/i6QgFkBg As you can see, no mention of the missing .so file at all. This made things really tough to investigate!

[richarddribeiro]

Hi,

I was one those that have spent hours trying to discover what was causing the loop. I only could see a few messages in the terminal showing that LightDM had started and finished. After that I began chasing the problem, trying things in TLP and several different kernels.

Thanks to @Photon89 I could fix the problem, that it was in a completely different library.

So, if we could have better information, we could help to fix the problem faster.