[Crash-utility] Re: Problem with using crash 4.0-2.21 on ppc

[Haren Myneni]

crash-utility-bounces at redhat.com wrote on 02/22/2006 07:31:43 AM:

> Rachita Kothiyal wrote:
> 
> >
> > > Rachita Kothiyal wrote:
> >
> >
> > >
> > > This happens in get_idle_threads() when perusing the runqueues 
array,
> > > where each per-cpu runqueue data structure contains a pointer to the
> > > idle (swapper) task for that CPU.  Now, this process requires that 
the
> > > per-cpu address manipulations are working correctly in order to find 
the
> > > each cpu's runqueue data structure.  It looks like the ppc64 change
> > > for per-cpu data accesses is suspect here:
> > >
> > > > Fix to recognize post-2.6.15 ppc64 kernels moving the 
per_cpu_offsets
> > > > to the "paca" structure.  Without this patch, crash fails with the
> > > > following error messages: "crash: cannot determine idle task 
addresses
> > > > from init_tasks[] or runqueues[]" and "crash: cannot resolve
> > > > init_task_union".  (pbadari at us.ibm.com)
> > >
> >
> > Right, but I thought this patch fixed this problem.
> > (I am using crash-4.0-2.21, and it includes this patch)
> 
> Right -- me too...   ;-)

Badari tested his patch on live system. He can give more information 
anyway. 

However, I used his patch for testing PPC64 vmcore before I post my patch. 
Did not see any issue when invoking crash tool. Tested on 2.6.16-rc2-gi9. 

I will also verify if I have the same vmcore.

Thanks
Haren


> 
> >
> >
> > > >
> > > > But I was able to run it ok on a live system.
> > > >
> > >
> > > Same kernel?  I have no idea why there would be a difference
> > > between live and vmcore.
> >
> > Yes, same kernel (2.6.16-rc4)
> >
> 
> I'm sure Badari can give you more information, but you might start
> by putting some debug printf's in his new ppc64_paca_init() function
> to see whether it's calculating the same kt->__per_cpu_offset[cpu]
> values on a live system vs. its associated vmcore?
> 
> Dave
> 
> 
> 
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