Re: [PATCH 5.15 64/76] proc: Use task_is_running() for wchan in /proc/$pid/stat

[Sasha Levin]

On Wed, Mar 13, 2024 at 08:04:36PM -0700, Kees Cook wrote:
> On Wed, Mar 13, 2024 at 12:42:11PM -0400, Sasha Levin wrote:
> > From: Kees Cook <keescook@xxxxxxxxxxxx>
> >
> > [ Upstream commit 4e046156792c26bef8a4e30be711777fc8578257 ]
> >
> > The implementations of get_wchan() can be expensive. The only information
> > imparted here is whether or not a process is currently blocked in the
> > scheduler (and even this doesn't need to be exact). Avoid doing the
> > heavy lifting of stack walking and just report that information by using
> > task_is_running().
> >
> > Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx>
> > Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
> > Link: https://lkml.kernel.org/r/20211008111626.211281780@xxxxxxxxxxxxx
> > Stable-dep-of: 60f92acb60a9 ("fs/proc: do_task_stat: move thread_group_cputime_adjusted() outside of lock_task_sighand()")
> > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
>
> Looks fine to me. Can you double-check that commit
> 54354c6a9f7f ("Revert "proc/wchan: use printk format instead of lookup_symbol_name()"")
> is already backported too?

Yup, it's there too.

--
Thanks,
Sasha