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

[Rachita Kothiyal]

On Wed, Feb 22, 2006 at 09:49:32AM -0500, Dave Anderson wrote:
> Rachita Kothiyal wrote:
> 
> > Hi
> >
> > I tried crash 4.0-2.21 on a 2.6.16-rc4 kernel on a ppc64
> > machine(Power5). Trying to analyse vmcore(from kdump) gave me
> > the following error:
> >
> > crash: pglist_data.node_mem_map structure member does not exist.
> > crash: certain memory-related commands will fail or display invalid data
> 
> This is to be expected on a CONFIG_SPARSEMEM kernel:
> 
> > If pglist_data.node_mem_map structure member does not exist, as in a
> > ppc64 kernel built with CONFIG_SPARSEMEM, print an init-time warning
> > message instead of failing with "crash: invalid structure member
> > offset: pglist_data.node_mem_map" message.  (haren at us.ibm.com,
> > anderson at redhat.com)

Ok.

> > crash: cannot determine idle task addresses from init_tasks[] or runqueues[]
> > crash: cannot resolve "init_task_union"
> >
> 
> 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)


> >
> > 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) 


Thanks
Rachita