[Crash-utility] crash: cannot resolve "init_task_union"

[Dave Anderson]

"Sachin P. Sant" wrote:

> Dave Anderson wrote:
> > On a RHEL5 x86:
> >
> >   crash> sym -q __per_cpu | grep -e start -e end
> >   c03100a0 (A) __per_cpu_start
> >   c0315ae4 (A) __per_cpu_end
> >   crash>
> >
> > But on your RHEL5 ppc64 kernel:
> >
> >   # nm -Bn vmlinux | grep __per_cpu
> >   c000000000430100 D __per_cpu_start
> >   c0000000004356f0 D __per_cpu_end
> >   #
> >
> > So if you remove the two "type == 'A'" qualifiers
> > from the if statement above, does it work OK?
> >
> Dave , thanks for the hint. Yes these symbols are of
> type D on PPC64 machine. Infact after checking on latest
> RHEL5 kernels [ with relocatable support ] this is
> the case with even other archs also.
>
> [root at llm19 boot]# cat System.map-2.6.18-1.2767.el5 | grep __per_cpu_
> c065dd2c r __ksymtab___per_cpu_offset
> c0663c64 r __kcrctab___per_cpu_offset
> c0666c12 r __kstrtab___per_cpu_offset
> c06e6b80 D __per_cpu_offset
> c077d100 D __per_cpu_start
> c0781de4 D __per_cpu_end
> [root at llm19 boot]# uname -i
> i386
> [root at llm19 boot]#
>

Yes, you are right -- I was looking at a much earlier
RHEL5 dumpfile...

>
> So this probably can be a generic problem affecting other arch's
> also.
>
> Thanks for the help.
>
> Attached here is a patch to fix this problem. Let me know if it's
> ok.
>
> Thanks
> -Sachin
>

Looks good -- queued for the next release.

Thanks,
  Dave


> * On a UP machine running SMP kernel, crash fails while reading idle tasks
> * from per cpu data.
>
> Signed-off-by : Sachin Sant <sachinp at in.ibm.com>
> ---
>
>   ------------------------------------------------------------------------------------------------------------------------
> * On a UP machine running SMP kernel, crash fails while reading idle tasks
> * from per cpu data.
>
> Signed-off-by : Sachin Sant <sachinp at in.ibm.com>
> ---
>
> diff -Naurp crash-4.0-3.16/kernel.c crash-4.0-3.16-new/kernel.c
> --- crash-4.0-3.16/kernel.c     2006-12-22 01:24:11.000000000 +0530
> +++ crash-4.0-3.16-new/kernel.c 2007-01-05 10:49:39.000000000 +0530
> @@ -114,7 +114,8 @@ kernel_init()
>
>         if ((sp1 = symbol_search("__per_cpu_start")) &&
>             (sp2 =  symbol_search("__per_cpu_end")) &&
> -           (sp1->type == 'A') && (sp2->type == 'A') &&
> +           (sp1->type == 'A' || sp1->type == 'D') &&
> +           (sp2->type == 'A' || sp2->type == 'D') &&
>             (sp2->value > sp1->value))
>                 kt->flags |= SMP|PER_CPU_OFF;
>
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