show_stack()/show_trace() prototypes

show_stack()/show_trace() prototypes

[David Mosberger]

Ingo, the ksymoops patch adds these to linux/sched.h:

extern void show_trace(unsigned long *stack);
extern void show_stack(unsigned long *stack);

This is not good.  In general, it is not possible to do a reliable
backtrace with just a stack pointer as a starting point (it is
necessary to have access to the entire "preserved" machine state
instead).  I'd suggest to either change the argument to a task_struct
pointer (and update half a dozen platforms or so accordingly), or to
leave the declarations platform-specific like they were before.

Thanks,

	--david

PS: force_sig_info() still drops the siginfo pointer passed to it.
    Will you fix this soon as promised?

Re: show_stack()/show_trace() prototypes

[Maciej W. Rozycki]

On Sat, 28 Sep 2002, David Mosberger wrote:

> Ingo, the ksymoops patch adds these to linux/sched.h:
> 
> extern void show_trace(unsigned long *stack);
> extern void show_stack(unsigned long *stack);
> 
> This is not good.  In general, it is not possible to do a reliable
> backtrace with just a stack pointer as a starting point (it is
> necessary to have access to the entire "preserved" machine state
> instead).  I'd suggest to either change the argument to a task_struct
> pointer (and update half a dozen platforms or so accordingly), or to
> leave the declarations platform-specific like they were before.

 Also the prototypes may differ, e.g. for MIPS/MIPS64 we have:

extern void show_trace(long *stack);

since MIPS addresses are signed and then, for consistency, we have:

extern void show_stack(long *stack);

as well.

-- 
+  Maciej W. Rozycki, Technical University of Gdansk, Poland   +
+--------------------------------------------------------------+
+        e-mail: macro@ds2.pg.gda.pl, PGP key available        +

Re: show_stack()/show_trace() prototypes

[Paul Mackerras]

David Mosberger writes:

> Ingo, the ksymoops patch adds these to linux/sched.h:
> 
> extern void show_trace(unsigned long *stack);
> extern void show_stack(unsigned long *stack);
> 
> This is not good.

I agree.  It is unnecessary to have these declarations in
linux/sched.h since these functions are only called from arch code.
So I would also vote for having the declarations arch-specific.

Paul.