What to do when Haiku system freezes or locks-up?

Was using my Zotac system I just purchased this last week and testing Haiku. Had Webpositive and media player running when my system froze. Weird thing is the audio locked onto endless skipping like an old record and would not stop. 1/2 the screen filled with text and I think I remember seeing something like KDBug at the end of the text.

Anyway, so there I was locked up, audio skipping the same beat over and over, no mouse, no control, nothing.

What may I ask is the proper thing to do in these cases when a system locks up and I have zero mouse control?

What I did was just shutoff the Zotac PC. I rebooted, relaunched the same two apps, playing a song, and it did the same thing. Basically I can lock it up at will. hehehe

Haiku R1 Alpha 3 on a Atom based Zotac PC. I will eventually do a Bug Report but will have to learn what to offer so it can be looked into.

Until then, what should I do to recover?

After the first two times shutting off the system from the power button all booted fine. On the 3rd time, booted fine, but Webpositive was hosed. It would launch but bring up no window and was stalled, can’t quit it from process viewer.

So, these lock ups and power down like I did killed Webpositive.

I did throw away the webpositive settings later (forget what folder I was in) and the relaunched and it ran again but not sure I want this happening all the time.

Any help would be nice.


Sometimes when you find yourself in KDL you can just type ‘continue’ and it will run a few more lines of the debugging code and then it might stop but you can keep typing ‘continue’ until it gives you some useful info on why its crashing. Ive had it bring itself out of KDL a few times this way also.

When that happens you have a problem that got you to KDL - Kernel Debug Land. It tells a lot of vital information about the problem and has a lot of commands to investigate it further. This is very useful for developers, to make sure they don’t occur again.
Please take a screenshot and report it, and what you were doing, when it occurs. Also this happens when there is a problem with the kernel, continuing when there is a problem with the kernel may lead to all sorts of problem.

It’s only with reports developers can track down and fix problems, making coming releases better. So please try to report problems.

There’s a link in the Welcome page with tips for a helpful bugreport. It’s also online.
If you experience KDLs often, you should run "checkfs " in Terminal from time to time to fix possible filesystem corruption.


Ah cool, will try that continue suggestion. Also will take a picture next time.

Tell me, is there a place in the OS once I boot again that may have this text as the last thing it did before it crashed?


I think I remember seeing something like KDBug at the end of the text.

Although the sequence of symbols you see when something goes wrong may mean nothing to you, it usually means plenty to an expert, and may provide just the information they need to fix the problem properly. Of course it’s much harder to remember the gist of something if you don’t understand what it means, so a very good idea is to take a digital photograph when something like this happens. You can either transcribe relevant parts to text at your leisure, or just upload the photograph. Try to make sure the text is in focus of course.

Some operating systems have clever tricks to ensure that the information is preserved by the computer itself in most cases, which saves you needing to do this, but it doesn’t hurt to know how.

Anyway, the reason the sound is “skipping like an old record” is that the sound chip contains a short ring buffer, typically a fraction of a second long, and it just constantly loops over this buffer when playing. The operating system’s sound drivers are responsible to updating sections of this buffer with new audio periodically. With the operating system frozen (probably waiting for you to type something) the drivers no longer update the buffer.

When all of the above doesn’t work, you can always press and hold ctrl+alt+del for five seconds or so and the system will reboot. This is not the optimal way to recover from a freeze/lockup, but when all else fails what can you do? Since Haiku uses such an awesome filesystem, data loss is rare!

Typing ‘help’ in KDL gives a huge list of commands that scrolls by too fast to read. IIRC, piping help to less or more will show a single page. And I think the crash log is kept in /var.log Posting that info can be useful also.