Re: [PATCH 2/2] x86: make __get_wchan() use arch_stack_walk()

[Qi Zheng]

On 2023/4/9 06:12, Josh Poimboeuf wrote:
> On Sat, Apr 08, 2023 at 01:36:06PM +0800, Qi Zheng wrote:
> > On 2023/4/8 13:08, Josh Poimboeuf wrote:
> > > On Thu, Mar 30, 2023 at 04:15:52PM +0800, Qi Zheng wrote:
> > > > Make __get_wchan() use arch_stack_walk() directly to
> > > > avoid open-coding of unwind logic.
> > > >
> > > > Signed-off-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx>
> > >
> > > Can we just have a shared version of __get_wchan() for all
> > > CONFIG_ARCH_STACKWALK arches?
> >
> >  From a quick glance, I think it's ok, but we still need to define
> > the arch's own get_wchan_cb(). I will try to do it.
>
> Hm, why would we need to do that?

Because I see checks for count++ < 16 exist in __get_wchan() for some
arches and some don't. So I'm not sure if this check can be discarded
after using arch_stack_walk(). And I see that this check is retained in
arm64, see [1] for details.

[1]. 
https://github.com/torvalds/linux/commit/4f62bb7cb165f3e7b0a91279fe9dd5c56daf3457

>

--
Thanks,
Qi