new panic in cpu_reset() with WITNESS

Andriy Gapon avg at
Mon Jan 23 14:01:23 UTC 2012

on 23/01/2012 15:07 Gleb Smirnoff said the following:
> On Mon, Jan 23, 2012 at 10:21:57AM +0200, Andriy Gapon wrote:
> A> > I can confirm that I can reboot succesfully with a new kernel
> A> > and kern.stop_scheduler_on_panic=0.
> A> 
> A> This is very puzzling.  You observation means that stop_scheduler_on_panic has
> A> an effect on the code outside the panic path.  I reviewed the
> A> SCHEDULER_STOPPED() changes and I still can not see how that could be possible
> A> (modulo compiler bugs).
> A> 
> A> Unfortunately, I also can not reproduce the problem here - without
> A> WITNESS_SKIPSPIN I am running into a panic[*] during boot.
> I suppose your patch (the one in other post) should help against
> this panic on boot.

Yes, it does.  It also masks/fixes the panic at reboot.

> A> BTW, do you get any other LOR reports _before_ you do a reboot?
> I have some, but I don't think they are related.


> A> Can you try to change printfs in witness to db_printfs?  Perhaps this will allow
> A> to get the details of the LOR in uart_cnputc.  Maybe that will reveal some
> A> important additional details.
> Should I do s/printf/db_printf/ throughout entire subr_witness.c, or only
> in special places?

I think that "replace all" should work for this test.

> A> Finally, can you try the patch from my other post?
> Yes, it works.

Thank you again.

Andriy Gapon

More information about the freebsd-current mailing list