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From: Sudeep Holla <sudeep.holla@arm.com>
To: Marc Zyngier <marc.zyngier@arm.com>
Cc: cai@gmx.us, open list <linux-kernel@vger.kernel.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	ard.biesheuvel@linaro.org, Jason Cooper <jason@lakedaemon.net>,
	Sudeep Holla <sudeep.holla@arm.com>
Subject: Re: WARNING: CPU: 0 PID: 0 at drivers/irqchip/irq-gic-v3-its.c
Date: Fri, 9 Nov 2018 17:28:04 +0000	[thread overview]
Message-ID: <CAPKp9uY7DOV9xMhCQcAC8yh0z3-=2U-CmZq064Br=d4VYrcg=A@mail.gmail.com> (raw)
In-Reply-To: <930d61db-6e44-8501-983d-09cd3759d153@arm.com>

On Fri, Nov 9, 2018 at 4:10 PM Marc Zyngier <marc.zyngier@arm.com> wrote:
>
[...]

>
> See bb42ca474010 and d003d029cea8 for details.
>
> Now, activating this workaround leads to lockdep being really angry,
> most likely because the cpus_read_lock is not taken, which is a change
> in behaviour...
>
> I'm trying to dig into this now.
>

Yes we found similar issue in kernel/sched/core.c sched_init_smp
There's a fix with detailed description in -next
(Commit 40fa3780bac2 ("sched/core: Take the hotplug lock in sched_init_smp()")

The behaviour changed since  commit cb538267ea1e ("jump_label/lockdep:
Assert we hold the hotplug lock for _cpuslocked() operations")

--
Regards,
Sudeep

  reply	other threads:[~2018-11-09 17:28 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-08 20:59 WARNING: CPU: 0 PID: 0 at drivers/irqchip/irq-gic-v3-its.c Qian Cai
2018-11-09 12:08 ` Marc Zyngier
2018-11-09 12:28   ` Qian Cai
2018-11-09 13:50     ` Marc Zyngier
2018-11-09 15:28       ` Qian Cai
2018-11-09 15:38         ` Marc Zyngier
2018-11-09 15:52           ` Qian Cai
2018-11-09 16:06             ` Marc Zyngier
2018-11-09 17:28               ` Sudeep Holla [this message]
2018-11-09 17:41                 ` Marc Zyngier
2018-11-09 18:41                   ` Qian Cai
2018-11-12  8:39                     ` Marc Zyngier
2018-12-02  4:16                       ` Qian Cai

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