Re: panic: double fault with 11.0-CURRENT r258504

From: Konstantin Belousov <kostikbel_at_gmail.com>
Date: Wed, 27 Nov 2013 21:20:08 +0200
On Wed, Nov 27, 2013 at 11:02:57AM -0800, Don Lewis wrote:
> On 27 Nov, Konstantin Belousov wrote:
> > On Wed, Nov 27, 2013 at 10:33:30AM -0800, Don Lewis wrote:
> >> On 27 Nov, Konstantin Belousov wrote:
> >> > On Wed, Nov 27, 2013 at 09:41:36AM -0800, Don Lewis wrote:
> >> >> On 27 Nov, Konstantin Belousov wrote:
> >> >> > On Wed, Nov 27, 2013 at 02:49:12AM -0800, Don Lewis wrote:
> >> >> >> <http://people.freebsd.org/~truckman/doublefault2.JPG>
> >> >> > 
> >> >> > What is the instruction at cpu_switch+0x9b ?
> >> >> 
> >> >> movl 0x8(%edx),%eax
> >> > So it is line 176 in swtch.s. Is machine still in ddb, or did you
> >> > obtained the core ? If yes, please print out the content of words at
> >> > 0xe4f62bb0 + 4, +8 (*), +16. Please print the content of the word at
> >> > address (*) + 8.
> >> 
> >> It is still in ddb.
> >> 
> >> <http://people.freebsd.org/~truckman/doublefault3.JPG>, though not in
> >> the above order.
> > Uhm, sorry, I mistyped the last part of the instructions.
> > 
> > The new thread pointer is 0xd2f4e000, there is nothing incriminating.
> > Please print the word at 0xd2f4e000+0x254 == 0xd2f4e254, which would be
> > the address of the new thread pcb. It is load from the pcb + 8 which
> > faults.
> 
> 0xf3d44d60
Again, the pointer looks fine, and its tail is 0xd60, which is correct for
the pcb offset in the last page of the thread stack.

Please do 'show thread 0xd2f4e000' before trying below instructions.

What happens if you try to read word at 0xf3d44d68 ?

Received on Wed Nov 27 2013 - 18:20:18 UTC

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