[Crash-utility] crash 4.0-2.8 fails on 2.6.14-rc5 (EM64T)

[Badari Pulavarty]

On Wed, 2005-10-26 at 16:27 -0400, Dave Anderson wrote:
> Badari Pulavarty wrote:
> 
> > On Wed, 2005-10-26 at 14:41 -0400, Dave Anderson wrote:
> > > Sorry I've generated some unnecesary confusion re: my comments
> > > about the use of DEFINE_PER_CPU and DECLARE_PER_CPU.
> > > That's what I get for trying to multi-task...
> > >
> > > Stepping back, the init_tss array is defined in "arch/x86_64/kernel/init_task.c".
> > >
> > > In 2.6.9, it's declared like so:
> > >
> > > /*
> > >  * per-CPU TSS segments. Threads are completely 'soft' on Linux,
> > >  * no more per-task TSS's. The TSS size is kept cacheline-aligned
> > >  * so they are allowed to end up in the .data.cacheline_aligned
> > >  * section. Since TSS's are completely CPU-local, we want them
> > >  * on exact cacheline boundaries, to eliminate cacheline ping-pong.
> > >  */
> > > DEFINE_PER_CPU(struct tss_struct, init_tss) ____cacheline_maxaligned_in_smp;
> > >
> > > In 2.6.13, it's slightly different in that it is initialized to INIT_TSS:
> > >
> > > /*
> > >  * per-CPU TSS segments. Threads are completely 'soft' on Linux,
> > >  * no more per-task TSS's. The TSS size is kept cacheline-aligned
> > >  * so they are allowed to end up in the .data.cacheline_aligned
> > >  * section. Since TSS's are completely CPU-local, we want them
> > >  * on exact cacheline boundaries, to eliminate cacheline ping-pong.
> > >  */
> > > DEFINE_PER_CPU(struct tss_struct, init_tss) ____cacheline_maxaligned_in_smp = INIT_TSS;
> > >
> > > Both kernels have the same DECLARE_PER_CPU in the
> > > "x86_64/processor.h" header file:
> > >
> > > DECLARE_PER_CPU(struct tss_struct,init_tss);
> > >
> > > That being the case, and not seeing why the INIT_TSS initialization should
> > > have anything to do with the problem at hand, I am officially stumped at
> > > why the 2.6.14 kernel shows the problem with your patch.
> >
> > Okay, I thought so too. I will take a closer look at it and let you
> > know what I find. I am tempted to go back to 2.6.10 and see if
> > crash works. Do you know the last known good kernel release for crash
> > to work ?
> >
> 
> Sorry -- for x86_64, I can't say that I do know the last version
> that worked.  Maybe somebody else on the list that uses other
> than Red Hat RHEL4 kernels does?
> 
> Dave
> 

Dave,

I tried 2.6.10 and crash worked fine there. Here is the what I found
interesting. On 2.6.10 the values seem reasonable, but on 2.6.14 they
have huge values.

2.6.10:
cpunum: 0 data_offset 10084b80f60
cpunum: 1 data_offset 10084b88f60

2.6.14-rc5:

cpunum: 0 data_offset ffff810084af5f60
cpunum: 1 data_offset ffff810084afdf60


I got curious on the top "0xffff8" part an trimmed them.
(basically I did data_offset & 0x00000fffffffffff).
Now I run into next problem :( I am missing something basic.

crash: read error: kernel virtual address: ffff81000000fa90  type:
"pglist_data node_next"

Thanks,
Badari