Re: diagnostic assertion curcpu()->ci_biglock_count == 0 failed

[Andrew Doran <ad%netbsd.org@localhost>]

Hi Thomas.

On Sun, Feb 23, 2020 at 10:30:24AM +0100, Thomas Klausner wrote:

> With a 9.99.47/amd64 kernel from February 16, I just had panic (handcopied):
> 
> panic: kernel diagnostic assertion "curcpu()->ci_biglock_count == 0" failed: file .../kern_exit.c line 214: kernel_lock leaked
> cpu12: Begin traceback
> vpanic
> kern_assert
> exit1
> sys_exit
> syscall
> -- syscall (number 1) --
> 70497d18609a
> cpu12: End trackback...
> Mutex error: mutex_vector_enter,542: locking against myself
> lock address: 0xffffa5ce94444b40
> current cpu:  12
> current lwp:  0xffffa5cbee57da80
> owner field:  0xffffa5cbee57da80 wait/spin: 0/0
> 
> Skipping crash dump on recursive panic
> 
> 
> It might have been a low-memory situation -- it was running a bulk
> build and had some network activity.

kardel@ has been running into this one too during bulk builds.  Something is
leaking a hold on kernel_lock, and it's not the LWP calling exit1() but
seems to be trapped there.  I will think about some additional diagnostics
that don't require LOCKDEBUG.

Andrew