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References: <20220917014746.3828349-1-floridsleeves@gmail.com> <Yyh/BmvAHNMlENFw@hirez.programming.kicks-ass.net>
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From:   Li Zhong <floridsleeves@gmail.com>
Date:   Mon, 19 Sep 2022 11:36:13 -0700
Message-ID: <CAMEuxRrmNT6xdLDiHLKb9COkRO31QuvwMX5zPFKw0uVAnJ6Yjg@mail.gmail.com>
Subject: Re: [PATCH v1] kernel/events/core: check return value of task_function_call()
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org,
        bpf@vger.kernel.org, namhyung@kernel.org, jolsa@kernel.org,
        alexander.shishkin@linux.intel.com, mark.rutland@arm.com,
        acme@kernel.org, mingo@redhat.com
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On Mon, Sep 19, 2022 at 7:39 AM Peter Zijlstra <peterz@infradead.org> wrote:
>
> On Fri, Sep 16, 2022 at 06:47:46PM -0700, Li Zhong wrote:
> > Check the return value of task_function_call(), which could be error
> > code when the execution fails.
>
> How is terminating the cgroup task iteration a useful thing? Also coding
> style fail for not adding { }

Thanks for your reply! Skip and continue the execution is more appropriate
here. Change it in v2 patch.

>
> > Signed-off-by: Li Zhong <floridsleeves@gmail.com>
> > ---
> >  kernel/events/core.c | 3 ++-
> >  1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/kernel/events/core.c b/kernel/events/core.c
> > index 2621fd24ad26..ac0cf611b12a 100644
> > --- a/kernel/events/core.c
> > +++ b/kernel/events/core.c
> > @@ -13520,7 +13520,8 @@ static void perf_cgroup_attach(struct cgroup_taskset *tset)
> >       struct cgroup_subsys_state *css;
> >
> >       cgroup_taskset_for_each(task, css, tset)
> > -             task_function_call(task, __perf_cgroup_move, task);
> > +             if (!task_function_call(task, __perf_cgroup_move, task))
> > +                     return;
> >  }
> >
> >  struct cgroup_subsys perf_event_cgrp_subsys = {
> > --
> > 2.25.1
> >