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From: Peter Zijlstra <peterz@infradead.org>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Dave Jones <davej@redhat.com>,
	Linux Kernel <linux-kernel@vger.kernel.org>
Subject: Re: WARN_ON_ONCE(in_nmi()) hit in irq_work_queue_on
Date: Thu, 7 Aug 2014 10:13:21 +0200	[thread overview]
Message-ID: <20140807081321.GI19379@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20140806234456.GA17015@localhost.localdomain>

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On Thu, Aug 07, 2014 at 01:44:58AM +0200, Frederic Weisbecker wrote:
> In fact the problem has arised since the recent irq work patches I did.

No, those just added the WARN, previously we send the resched IPI, and
that's equally wrong from NMI context.

> There I've changed tick_nohz_full_kick() to use irq_work_queue_on() instead
> of irq_work_queue() so it has become NMI unsafe by accident.
> 
> So I'd rather suggest this instead of queuing two levels of irq_work:

> +void tick_nohz_full_kick(void)
> +{
> +	if (!tick_nohz_full_cpu(smp_processor_id()))
> +		irq_work_queue(&__get_cpu_var(nohz_full_kick_work));
> +}

Indeed, that's better. Thanks!

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  reply	other threads:[~2014-08-07  8:13 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-08-06 16:21 WARN_ON_ONCE(in_nmi()) hit in irq_work_queue_on Dave Jones
2014-08-06 16:46 ` Peter Zijlstra
2014-08-06 16:56   ` Peter Zijlstra
2014-08-06 17:01     ` Peter Zijlstra
2014-08-06 23:44       ` Frederic Weisbecker
2014-08-07  8:13         ` Peter Zijlstra [this message]
2014-08-07 12:58           ` Frederic Weisbecker
2014-08-07 13:15             ` Peter Zijlstra
2014-08-07 13:18               ` Frederic Weisbecker

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