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From: Steven Rostedt <rostedt@goodmis.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Ingo Molnar <mingo@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>
Subject: Re: [patch 17/18] sched: Enable might_sleep() checks early
Date: Tue, 16 May 2017 09:14:12 -0400	[thread overview]
Message-ID: <20170516091412.77987500@gandalf.local.home> (raw)
In-Reply-To: <alpine.DEB.2.20.1705160923070.1934@nanos>

On Tue, 16 May 2017 09:33:52 +0200 (CEST)
Thomas Gleixner <tglx@linutronix.de> wrote:


> Darn, forgot about PREEMPT_VOLUNTARY and that excellent changelog does not
> mention it either. 
> 
> > So if we schedule to the kernel_init() task before we set kthreadd_task
> > we'll try and spawn kthreads and OOPS.  
> 
> So back to Stevens question. No, we can't set the state earlier than right
> before schedule() simply because with PREEMPT preemption _is_ actually
> disabled and kernel_kthread() will trigger might_sleep() splats.

So a comment in the code mentioning PREEMPT_VOLUNTARY might be
advantageous.

> 
> What a mess.

Indeed.

-- Steve

  reply	other threads:[~2017-05-16 13:14 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-14 18:27 [patch 00/18] init: Enable might_sleep() and smp_processor_id() debugging early Thomas Gleixner
2017-05-14 18:27 ` [patch 01/18] init: Pin init task to boot cpu initially Thomas Gleixner
2017-05-15 14:10   ` Steven Rostedt
2017-05-14 18:27 ` [patch 02/18] arm: Adjust system_state check Thomas Gleixner
2017-05-14 18:27 ` [patch 03/18] arm64: " Thomas Gleixner
2017-05-14 18:27 ` [patch 04/18] x86/smp: " Thomas Gleixner
2017-05-15 14:17   ` Steven Rostedt
2017-05-14 18:27 ` [patch 05/18] metag: " Thomas Gleixner
2017-05-14 18:27 ` [patch 06/18] powerpc: " Thomas Gleixner
2017-05-15  9:19   ` Michael Ellerman
2017-05-14 18:27 ` [patch 07/18] ACPI: " Thomas Gleixner
2017-05-15 10:20   ` Mark Rutland
2017-05-15 10:25     ` Thomas Gleixner
2017-05-15 14:27   ` Steven Rostedt
2017-05-16 18:13     ` Thomas Gleixner
2017-05-14 18:27 ` [patch 08/18] mm: " Thomas Gleixner
2017-05-15  6:18   ` Greg Kroah-Hartman
2017-05-15 14:33     ` Steven Rostedt
2017-05-14 18:27 ` [patch 09/18] cpufreq/pasemi: " Thomas Gleixner
2017-05-15  5:24   ` Viresh Kumar
2017-05-15 14:34     ` Steven Rostedt
2017-05-14 18:27 ` [patch 10/18] iommu/vt-d: Adjust system_state checks Thomas Gleixner
2017-05-15 14:42   ` Joerg Roedel
2017-05-14 18:27 ` [patch 11/18] iommu/of: Adjust system_state check Thomas Gleixner
2017-05-15 10:45   ` Robin Murphy
2017-05-15 14:42   ` Joerg Roedel
2017-05-14 18:27 ` [patch 12/18] async: Adjust system_state checks Thomas Gleixner
2017-05-14 18:39   ` Arjan van de Ven
2017-05-14 18:27 ` [patch 13/18] extable: " Thomas Gleixner
2017-05-15 14:37   ` Steven Rostedt
2017-05-14 18:27 ` [patch 14/18] printk: " Thomas Gleixner
2017-05-15 14:53   ` Steven Rostedt
2017-05-14 18:27 ` [patch 15/18] mm/vmscan: " Thomas Gleixner
2017-05-15 14:54   ` Steven Rostedt
2017-05-14 18:27 ` [patch 16/18] init: Introduce SYSTEM_BOOTING_UP/SMP states Thomas Gleixner
2017-05-15  9:58   ` Juergen Gross
2017-05-15 14:58   ` Steven Rostedt
2017-05-14 18:27 ` [patch 17/18] sched: Enable might_sleep() checks early Thomas Gleixner
2017-05-15 15:10   ` Steven Rostedt
2017-05-15 19:12     ` Thomas Gleixner
2017-05-16  7:14       ` Peter Zijlstra
2017-05-16  7:33         ` Thomas Gleixner
2017-05-16 13:14           ` Steven Rostedt [this message]
2017-05-14 18:27 ` [patch 18/18] sched: Enable smp_processor_id() " Thomas Gleixner
2017-05-15 15:12   ` Steven Rostedt
2017-05-15 15:36     ` Thomas Gleixner
2017-05-15 11:53 ` [patch 00/18] init: Enable might_sleep() and smp_processor_id() debugging early Mark Rutland

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