Re: [PATCH 3/5] dump_stack: consolidate dump_stack()implementations and unify their behaviors

From: Martin Schwidefsky
Date: Tue Apr 02 2013 - 02:48:41 EST


On Sat, 30 Mar 2013 12:45:35 +0100
Heiko Carstens <heiko.carstens@xxxxxxxxxx> wrote:

> On Fri, Mar 29, 2013 at 07:27:06PM -0700, Tejun Heo wrote:
> > Both dump_stack() and show_stack() are currently implemented by each
> > architecture. show_stack(NULL, NULL) dumps the backtrace for the
> > current task as does dump_stack(). On some archs, dump_stack() prints
> > extra information - pid, utsname and so on - in addition to the
> > backtrace while the two are identical on other archs.
>
> [...]
>
> > This patch expands the dummy fallback dump_stack() implementation in
> > lib/dump_stack.c such that it prints out debug information (taken from
> > x86) and invokes show_stack(NULL, NULL) and drops arch-specific
> > dump_stack() implementations in all archs except blackfin and s390.
> > Blackfin's dump_stack() does something wonky that I don't understand
> > and s390 prints its own debug information which includes fields which
> > aren't accessible from arch-indepdent code.
>
> The couple of extra fields aren't worth an s390 version of dump_stack()
> that differs from all other architectures.
> Please drop the s390 version as well. Thanks!

Hmm, we would lose task_thread_info(current)->cpu and current->thread.ksp,
I don't care much about the kernel stack pointer which has been stored at
the last call to __switch_to but the cpu number might be interesting.
Could we add the cpu number to the generic dump_stack version?

--
blue skies,
Martin.

"Reality continues to ruin my life." - Calvin.

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