Re: [PATCH] irqchip/gic-v4.1: Use readx_poll_timeout_atomic() to fix sleep in atomic

From: Marc Zyngier <maz@kernel.org>
To: Zenghui Yu <yuzenghui@huawei.com>
Cc: linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	kvmarm@lists.cs.columbia.edu, tglx@linutronix.de,
	jason@lakedaemon.net, wanghaibin.wang@huawei.com,
	wangjingyi11@huawei.com
Subject: Re: [PATCH] irqchip/gic-v4.1: Use readx_poll_timeout_atomic() to fix sleep in atomic
Date: Wed, 10 Jun 2020 16:02:54 +0100	[thread overview]
Message-ID: <2bff9c0af0aa5eeef44b381ee0f8a542@kernel.org> (raw)
In-Reply-To: <4a9822bd-0362-7ffe-6e56-3f05a7816d9e@huawei.com>

Hi Zenghui,

On 2020-06-10 14:59, Zenghui Yu wrote:
> Hi Marc,
> 
> Sorry to ping you in the merge window, but ...
> 
> On 2020/6/5 13:23, Zenghui Yu wrote:
>> readx_poll_timeout() can sleep if @sleep_us is specified by the 
>> caller,
>> and is therefore unsafe to be used inside the atomic context, which is
>> this case when we use it to poll the GICR_VPENDBASER.Dirty bit in
>> irq_set_vcpu_affinity() callback.
> 
> this seems like an urgent thing to me. Without this patch, CPUs are
> easily to get stuck on my board with GICv4.1 enabled. So it'd be good 
> if
> you can have a look and take this as a fix (if it is correct).

No worries. I've earmarked the patch for -rc1 already, just haven't got
a chance to build the branch yet (a bit busy on the KVM side).

I'll probably update the branch tonight or tomorrow.

Thanks,

         M.
-- 
Jazz is not dead. It just smells funny...