From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: Re: Regression with suspicious RCU usage splats with cpu_pm change
Date: Thu, 13 Jul 2017 05:43:18 -0700
Message-ID: <20170713124318.GK2393@linux.vnet.ibm.com>
References: <20170713070749.GE16509@atomide.com>
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To: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Alex Shi <alex.shi@linaro.org>, Tony Lindgren <tony@atomide.com>, Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, Linux PM <linux-pm@vger.kernel.org>, Linux OMAP Mailing List <linux-omap@vger.kernel.org>, Catalin Marinas <catalin.marinas@arm.com>, Will Deacon <Will.Deacon@arm.com>
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On Thu, Jul 13, 2017 at 01:50:26PM +0200, Rafael J. Wysocki wrote:
> On Thu, Jul 13, 2017 at 11:43 AM, Alex Shi <alex.shi@linaro.org> wrote:
> >
> > On 07/13/2017 03:07 PM, Tony Lindgren wrote:
> >> Hi,
> >>
> >> Looks like next-20170713 gives me a bunch of "suspicious RCU usage"
> >> splats with cpuidle_coupled on duovero, see below. I bisected it down
> >> to commit 2f027e003d05 ("cpu_pm: replace raw_notifier with
> >> atomic_notifier").
> 
> OK, so I'm dropping this commit.

You can surround idle-loop RCU-reading code with RCU_NONIDLE().
This will tell RCU to pay attention even though the CPU is otherwise
idle.

							Thanx, Paul