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Date:   Thu, 4 May 2023 17:30:57 +0200
From:   Peter Zijlstra <peterz@infradead.org>
To:     Oleg Nesterov <oleg@redhat.com>
Cc:     Wander Lairson Costa <wander@redhat.com>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Ian Rogers <irogers@google.com>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Will Deacon <will@kernel.org>,
        Waiman Long <longman@redhat.com>,
        Boqun Feng <boqun.feng@gmail.com>,
        Juri Lelli <juri.lelli@redhat.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
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        Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
        Daniel Bristot de Oliveira <bristot@redhat.com>,
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        "Eric W. Biederman" <ebiederm@xmission.com>,
        Brian Cain <bcain@quicinc.com>,
        Kefeng Wang <wangkefeng.wang@huawei.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        "Liam R. Howlett" <Liam.Howlett@oracle.com>,
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        Shakeel Butt <shakeelb@google.com>,
        open list <linux-kernel@vger.kernel.org>,
        "open list:PERFORMANCE EVENTS SUBSYSTEM" 
        <linux-perf-users@vger.kernel.org>, Hu Chunyu <chuhu@redhat.com>,
        Paul McKenney <paulmck@kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [PATCH v7 2/3] sched/task: Add the put_task_struct_atomic_safe()
 function
Message-ID: <20230504153057.GI1744258@hirez.programming.kicks-ass.net>
References: <20230425114307.36889-1-wander@redhat.com>
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 <20230504122945.GA28757@redhat.com>
 <20230504143303.GA1744142@hirez.programming.kicks-ass.net>
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On Thu, May 04, 2023 at 05:23:07PM +0200, Oleg Nesterov wrote:
> On 05/04, Wander Lairson Costa wrote:
> >
> > On Thu, May 4, 2023 at 11:34 AM Peter Zijlstra <peterz@infradead.org> wrote:
> > >
> > > static inline void put_task_struct(struct task_struct *t)
> > > {
> > >         if (!refcount_dec_and_test(&t->usage))
> > >                 return;
> > >
> > >         if (IS_ENABLED(CONFIG_PREEMPT_RT) && !preemptible())
> > >                 call_rcu(&t->rcu, __put_task_struct_rcu);
> > >
> > >         __put_task_struct(t);
> > > }
> > >
> >
> > That's what v5 [1] does.
> 
> Yes, but as Sebastian explained CONFIG_PROVE_RAW_LOCK_NESTING won't like it.

This can help:

  https://lkml.kernel.org/r/168303194177.404.8610123576035502891.tip-bot2@tip-bot2