Kernel Debugging Land in Haiku: Your best of

While I find Haiku rather stable, I sometimes run into KDL. Unfortunately, most of the time, it’s not possible to reproduce it (random KDL), but on the other hand it’s often involving the same programs. So maybe we could try to trace the most common cases, and maybe open a bug in the tracker according to this.

I got KDL:

  • Several times while renaming a file on a fat32 usb key (after reboot I could rename them correctly)
  • Several times while accessing a .Trashes/501 folder on the same fat32 usb key (either by tracker or by the terminal, when trying to enter this folder or delete it). It did it every time I accessed this folder, so it’s probably a persistent bug, even though I haven’t tested it on another usb key (it’s a fat32 usbkey I’m using on Linux too, the reason for the .Trashes folder)
  • Trying to run a makefile on a fat32 FS.

So most of the time it was when accessing a fat32 FS (I understood the advice to mount the usb key in Read mode only, but I need it to synchronise and save my files onto my linux system, since ext2 is not supported), but fortunately:

  • it never happened while normally editing and saving a text file on this FS.
  • it never led to data corruption, on the contrary to mac os x which erased everying on a fat32 usb drive when it couldn’t read a file from it…

The only other KDL I got while not accessing a fat32 FS was:

  • Twice or three times while reading or closing a pdf written in my home or on the desktop. (after reboot I could read / close them correctly)

It KDLs maybe 1 time in 20 immediately after double clicking to start Thunderbird, especially if Thunderbird was in fact already open and minimized and I didn’t notice. The message has something to do with a semaphore or lock (wish I remembered exactly). I think this could probably be tracked down, if someone put a little effort into it and had Thunderbird compiling from source. The Thunderbird port is probably doing something wrong, but of course the point is that being naughty should crash Thunderbird, not the kernel.

There is several Trac tickets regarding fat support bugs.
Make a quick search to see if it’s an already known bug, and if it’s not, feel free to create your own. At worst, if it’s a duplicate one, it will shortly be identified as is. Meanwhile, the fat pending issues will again get some attention, which can’t be a bad thing.

If you can, try to capture the KDL message. If nothing better, a camera shot of your KDL screen, while it’s readable enough, is valuable too.
Ideally, while in KDL, dump the call stack (type bt or sc command).

Anyway, nice to see that you’re still using Haiku long after your one-week-with review