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Date:   Thu, 19 May 2022 17:04:06 +0200
From:   Frederic Weisbecker <frederic@kernel.org>
To:     Peter Zijlstra <peterz@infradead.org>
Cc:     LKML <linux-kernel@vger.kernel.org>, Phil Auld <pauld@redhat.com>,
        Alex Belits <abelits@marvell.com>,
        Nicolas Saenz Julienne <nsaenz@kernel.org>,
        Xiongfeng Wang <wangxiongfeng2@huawei.com>,
        Neeraj Upadhyay <quic_neeraju@quicinc.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Yu Liao <liaoyu15@huawei.com>,
        Boqun Feng <boqun.feng@gmail.com>,
        "Paul E . McKenney" <paulmck@kernel.org>,
        Marcelo Tosatti <mtosatti@redhat.com>,
        Paul Gortmaker <paul.gortmaker@windriver.com>,
        Uladzislau Rezki <uladzislau.rezki@sony.com>,
        Joel Fernandes <joel@joelfernandes.org>
Subject: Re: [PATCH 03/21] rcu: Add a note about noinstr VS unsafe eqs
 functions
Message-ID: <20220519150406.GB618878@lothringen>
References: <20220503100051.2799723-1-frederic@kernel.org>
 <20220503100051.2799723-4-frederic@kernel.org>
 <20220519150026.GK2578@worktop.programming.kicks-ass.net>
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On Thu, May 19, 2022 at 05:00:26PM +0200, Peter Zijlstra wrote:
> On Tue, May 03, 2022 at 12:00:33PM +0200, Frederic Weisbecker wrote:
> > @@ -895,6 +899,10 @@ static void noinstr rcu_eqs_exit(bool user)
> >   *
> >   * If you add or remove a call to rcu_idle_exit(), be sure to test with
> >   * CONFIG_RCU_EQS_DEBUG=y.
> > + *
> > + * FIXME: This function should be noinstr but the below local_irq_save() is
> > + * unsafe because it involves illegal RCU uses through tracing and lockdep.
> > + * This must be fixed first.
> >   */
> >  void rcu_idle_exit(void)
> >  {
> 
> Urgh, except this one... I'm sure I fixed that at some point. Clearly
> that never made it in :/

Most definetly the trickiest one...