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From: Peter Zijlstra <peterz@infradead.org>
To: Guenter Roeck <linux@roeck-us.net>
Cc: rafael@kernel.org, viresh.kumar@linaro.org, mingo@kernel.org,
	x86@kernel.org, mark.rutland@arm.com, will@kernel.org,
	svens@linux.ibm.com, linux-kernel@vger.kernel.org,
	Heiko Carstens <hca@linux.ibm.com>,
	Vasily Gorbik <gor@linux.ibm.com>,
	Christian Borntraeger <borntraeger@de.ibm.com>,
	linux-s390@vger.kernel.org
Subject: Re: [PATCH 1/2] sched/idle: Fix arch_cpu_idle() vs tracing
Date: Tue, 1 Dec 2020 12:02:09 +0100	[thread overview]
Message-ID: <20201201110209.GQ3040@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20201130210003.GA40619@roeck-us.net>

On Mon, Nov 30, 2020 at 01:00:03PM -0800, Guenter Roeck wrote:
> On Fri, Nov 20, 2020 at 12:41:46PM +0100, Peter Zijlstra wrote:
> > We call arch_cpu_idle() with RCU disabled, but then use
> > local_irq_{en,dis}able(), which invokes tracing, which relies on RCU.
> > 
> > Switch all arch_cpu_idle() implementations to use
> > raw_local_irq_{en,dis}able() and carefully manage the
> > lockdep,rcu,tracing state like we do in entry.
> > 
> > (XXX: we really should change arch_cpu_idle() to not return with
> > interrupts enabled)
> > 
> 
> Has this patch been tested on s390 ? Reason for asking is that it causes
> all my s390 emulations to crash. Reverting it fixes the problem.

My understanding is that it changes the error on s390. Previously it
would complain about the local_irq_enable() in arch_cpu_idle(), now it
complains when taking an interrupt during idle.

  reply	other threads:[~2020-12-01 11:03 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20201120114145.197714127@infradead.org>
2020-11-20 11:41 ` [PATCH 1/2] sched/idle: Fix arch_cpu_idle() vs tracing Peter Zijlstra
2020-11-20 12:39   ` Mark Rutland
2020-11-25 13:57   ` [tip: locking/urgent] " tip-bot2 for Peter Zijlstra
2020-11-30 21:00   ` [PATCH 1/2] " Guenter Roeck
2020-12-01 11:02     ` Peter Zijlstra [this message]
2020-12-01 11:12       ` Sven Schnelle
2020-12-01 11:56       ` Sven Schnelle
2020-12-01 12:52         ` Peter Zijlstra
2020-12-01 13:06           ` Guenter Roeck
2020-12-01 13:38           ` Will Deacon
2020-12-01 14:51         ` Peter Zijlstra

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