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SubjectRe: [PATCH] show_task() and thread_saved_pc() fix for x86
On Tue, Nov 14, 2000 at 10:19:32AM +0100, Jean Wolter wrote:

> > > OTOH, the value is used only by Alt-SysRq-T, so... Hell knows.
> >
> > No, it's also used by 'ps -l'. See wchan.
>
> ps -l uses get_wchan() (an architecture specific function from
> arch/*/kernel/process.c) to get the return address from
> schedule(). And now thread_saved_pc() seems to do the same (at least
> on x86). Is there any reason to have two architecture specific
> functions doing the same or do I miss something?
>
> Jean
>
> PS: Architectures other then x86 use thread_saved_pc() to implement
> get_wchan(). If the debug output of Alt-SysRq-T is supposed to show
> the waiting channel we should use get_wchan() instead of thread_saved_pc().

Probably historic reasons, it's been that way as long as I can think back.
Yet the use of thread_saved_pc() in kernel/sched.c should imho be considered
a buglet and be replaced by get_wchan to get more meaningful debugging
information.

Ralf
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