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ReturnInfinity / BareMetal

A very minimal, resource efficient exo-kernel
http://www.returninfinity.com
MIT License
620 stars 89 forks source link

Random lockups when running in qemu #58

Closed dosadi closed 1 year ago

dosadi commented 4 years ago

First off, sorry this bug report isn't too specific about a number of things, mostly involving steps to reproduce the problem... Anyway, the problem is that BM hangs a lot. I have been playing with modifying the c source for the hello world demo app, by doing simple things like adding another line of output using b_output(), and it will often hang up and not go back to the command prompt. Other times it will print both lines correctly, but adding any more code after that and it starts hanging again.

I've tried recompilation without any code changes, and it has acted differently both times! Sometimes there is a message about an interrupt being handled, other times it just silently crashes. I've tried building my own qemu binary from current git sources, but the problem persists. The BM tree is from current git, too....

Go ahead and close this bug if you are unable to reproduce it, and I'll chalk it up to not wearing my tinfoil hat or something :-). I just wanted to vent. And please let me know if there is a good way to track down the problem, too - maybe I could get someone some debug logs or something.

IanSeyler commented 4 years ago

Can you reproduce this with the latest source code?

dosadi commented 4 years ago

Yes, I tried it with a fresh git clone.

ghost commented 4 years ago

Go ahead and close this bug if you are unable to reproduce it, and I'll chalk it up to not wearing my tinfoil hat or something :-).

First, try taking the tinfoil hat off and putting it back on again.

Secondly, do you have a system monitor that you can check to see what's causing the hang up? That might indicate if it's a disk program or a CPU program.

dosadi commented 4 years ago

On the host, I can run 'top', which shows that the "qemu-system-x86" process is consuming around 100% of the CPU once the hangup condition shows itself:

PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND

3774 jon 20 0 1322064 162296 59716 S 102.3 4.2 1:07.79 qemu-system-x86

If you do some Google searching, you will find some scattered references over the years to a problem with QEMU where it locks up and the CPU used by the qemu-x-y process spikes to around 100%. I'm not sure if this is a factor in this particular case, but it's all I could find in the way of a case for blaming the problem on QEMU instead of the BM guest code....

IanSeyler commented 1 year ago

Closing this as it is quite old and was not able to be duplicated.