From: Catalin Marinas <catalin.marinas@arm.com>
To: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Andrey Ryabinin <aryabinin@virtuozzo.com>
Subject: Re: [PATCH] sched, cpuidle: Do not access cpuidle_devices when !CONFIG_CPU_IDLE
Date: Wed, 1 Jun 2016 22:48:37 +0100 [thread overview]
Message-ID: <20160601214836.GA14666@mbp> (raw)
In-Reply-To: <4245615.v9qo6igreM@vostro.rjw.lan>
On Wed, Jun 01, 2016 at 10:20:03PM +0200, Rafael J. Wysocki wrote:
> On Wednesday, June 01, 2016 06:52:16 PM Catalin Marinas wrote:
> > The cpuidle_devices per-CPU variable is only defined when CPU_IDLE is
> > enabled. Commit c8cc7d4de7a4 ("sched/idle: Reorganize the idle loop")
> > removed the #ifdef CONFIG_CPU_IDLE around cpuidle_idle_call() with the
> > compiler optimising away __this_cpu_read(cpuidle_devices). However, with
> > CONFIG_UBSAN && !CONFIG_CPU_IDLE, this optimisation no longer happens
> > and the kernel fails to link since cpuidle_devices is not defined.
> >
> > This patch introduces an accessor function for the current CPU cpuidle
> > device (returning NULL when !CONFIG_CPU_IDLE) and uses it in
> > cpuidle_idle_call().
> >
> > Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
> > Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
> > Cc: Ingo Molnar <mingo@redhat.com>
> > Cc: Peter Zijlstra <peterz@infradead.org>
> > Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
> > Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
>
> OK
>
> Is this needed in -stable?
Not sure how common this config combination is (I was just testing
different options and came across it). Even though it's not a fix for
UBSAN, we could add it up to 4.5 since that's when UBSAN was merged:
Cc: <stable@vger.kernel.org> # 4.5+
--
Catalin
prev parent reply other threads:[~2016-06-01 21:48 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-01 17:52 [PATCH] sched, cpuidle: Do not access cpuidle_devices when !CONFIG_CPU_IDLE Catalin Marinas
2016-06-01 20:20 ` Rafael J. Wysocki
2016-06-01 21:48 ` Catalin Marinas [this message]
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