spin lock sched lock held by 0xffffff007b712250 for > 5 seconds

[John Baldwin]

On Friday 16 July 2004 12:21 pm, Robert Watson wrote:
> On Fri, 16 Jul 2004, Willem Jan Withagen wrote:
> > After todays kernelbuild the system seem to be a lot better...
> > It can take quite some buildworld abuse, but still:
> >
> > spin lock sched lock held by 0xffffff007b712250 for > 5 seconds
> > panic: spin lock held too long
> > cpuid = 1;
> > KDB: enter: panic
> >
> > But I'm not shure what I could/should do now, since the KDB
> > introduction.  Normally I'd expect to see:  db>
>
> We have trouble entering the debugger when in a critical section/and or
> have sched_lock held -- I think this is because we try to halt the other
> CPUs and that gets nastily stuck in some form.  We need to fix this.
>
> This could well be a symptom of some of the other hangs we've been seeing,
> and I've seen similar things on my test box with preemption enabled.

You can hack sys/i386/include/smptests.h (or smptest.h, whichever it is) and 
comment out CPUSTOP_ONDDBREAK as a hack.  I did that recently for some 
debugging.

-- 
John Baldwin <jhb at FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve"  =  http://www.FreeBSD.org