On Thu, 2008-07-17 at 00:12 +0200, Arnd Bergmann wrote:
> We need to pass the kernel stack pointer instead of the user space
> stack pointer in save_stack_trace_tsk().
>
> Signed-off-by: Arnd Bergmann <[EMAIL PROTECTED]>
>
> On Wednesday 16 July 2008, Nathan Lynch wrote:
> > Arnd Bergmann wrote:
> > > Implement save_stack_trace_tsk on powerpc, so that we can run with
> > > latencytop.
> >
> > So I tried latencytop with linux-next and got the following oops, but
> > I didn't really look into it yet.
>
> Oh, I didn't even realize that benh had merged that patch of mine.
> As I wrote in the description, it was entirely untested. You found
> another obvious bug: The code was passing the user space stack
> pointer instead of the kernel stack pointer.
>
> Again, this patch is entirely untested, and I would not be at all
> surprised to find other trivial bugs.
I missed that part of your description and it didn't seem to break the
kernel stack trace so ... :-) It's a nice feature to have and bugs can
be fixed before release.
Now we should probably look at making the stacktrace code a bit more
robust vs. wild pointers anyway.
> --- a/arch/powerpc/kernel/stacktrace.c
> +++ b/arch/powerpc/kernel/stacktrace.c
> @@ -59,6 +59,6 @@ EXPORT_SYMBOL_GPL(save_stack_trace);
>
> void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
> {
> - save_context_stack(trace, tsk->thread.regs->gpr[1], tsk, 0);
> + save_context_stack(trace, tsk->thread.ksp, tsk, 0);
> }
> EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
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