Re: panic: double fault with 11.0-CURRENT r258504

From: Don Lewis <truckman_at_FreeBSD.org>
Date: Wed, 27 Nov 2013 02:41:30 -0800 (PST)
On 27 Nov, Konstantin Belousov wrote:
> On Wed, Nov 27, 2013 at 01:13:41AM -0800, Don Lewis wrote:
>> On 27 Nov, Konstantin Belousov wrote:
>> > On Wed, Nov 27, 2013 at 12:22:27AM -0800, Don Lewis wrote:
>> >> It took a while, but I just got another double fault, though this one is
>> >> somewhat different.  This time it trapped in cpu_switch(), which
>> >> resulted in calls to
>> >> trap()->printf()->...->putchar()->msgbuf_addstr()->_mtx_lock_spin_flags()
>> >> where it trapped again.
>> >> 
>> >> Sitting at DDB prompt ...
>> > 
>> > Does 'show allpcpu' work ?
>> 
>> Yup.  For both CPUs, curthread == idlethread, both CPUs have the same
>> curpcb.  What is "dynamic pcpu"?  The values differ considerably between
>> the two CPUs.
> 
> Are you sure about curpcb being the same for two CPUs ? This is rather
> broken.  The best would be to show the actual ddb output.

It turns out that they are different:
	0xe4f62d60
	0xe4f65d60

Screenshot here: <http://people.freebsd.org/~truckman/doublefault1.JPG>

> Dynamic pcpu is in fact 'static' pcpu which is allocated for modules.
> It must be per-cpu, so different values are correct.
Received on Wed Nov 27 2013 - 09:41:38 UTC

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