Re: [patch 00/18] init: Enable might_sleep() and smp_processor_id() debugging early

From	Mark Rutland <mark.rutland@arm.com>
Newsgroups	linux.kernel
Subject	Re: [patch 00/18] init: Enable might_sleep() and smp_processor_id() debugging early
Date	2017-05-15 14:00 +0200
Message-ID	<tHmPo-7IC-11@gated-at.bofh.it> (permalink)
References	<tH6AV-56V-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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Hi Thomas,

On Sun, May 14, 2017 at 08:27:16PM +0200, Thomas Gleixner wrote:
> We recentlty discovered a call path which takes a mutex from the low level
> secondary CPU bringup code and wondered why this was not caught by
> might_sleep().
> 
> The reason is that both debug facilities depend on system_state ==
> SYSTEM_RUNNING, which is set after init memory is freed.
> 
> That means that the SMP bootup and the builtin driver initialization is not
> covered by these checks at all.
> 
> The patch series addresses this by adding two intermediate
> states. might_sleep() debugging is enabled right when scheduling starts,
> i.e. the boot CPU idle task schedules the first time. smp_processor_id()
> debugging is enabled right before SMP bringup happens.

Thanks for putting this together!

I've tested the series on a Juno R1 (arm64) system, with both DT and
ACPI.

Patch 17 finds the arm64 mutex issue [1] we discussed previously.

Otherwise, no new issues spotted with this on arm64, just an (existing)
ACPI PMU issue for which I've evidently not run sufficient checks on.

So for the bits relevant to arm64 (patches 1, 3, 7, 8, and 12-18):

Tested-by: Mark Rutland <mark.rutland@arm.com>

Thanks,
Mark.

[1] https://lkml.kernel.org/r/20170511125430.GD14766@leverpostej

> 
> Thanks,
> 
> 	tglx
> ----
>  arch/arm/kernel/smp.c            |    3 +--
>  arch/metag/kernel/smp.c          |    3 +--
>  arch/x86/kernel/smpboot.c        |    2 +-
>  b/arch/arm64/kernel/smp.c        |    3 +--
>  b/arch/powerpc/kernel/smp.c      |    2 +-
>  drivers/acpi/pci_root.c          |    2 +-
>  drivers/base/node.c              |    2 +-
>  drivers/cpufreq/pasemi-cpufreq.c |    2 +-
>  drivers/iommu/intel-iommu.c      |    4 ++--
>  drivers/iommu/of_iommu.c         |    2 +-
>  drivers/xen/manage.c             |    2 ++
>  include/linux/kernel.h           |    2 ++
>  init/main.c                      |   12 ++++++++++--
>  kernel/async.c                   |    8 ++++----
>  kernel/extable.c                 |    2 +-
>  kernel/printk/printk.c           |    2 +-
>  kernel/sched/core.c              |    4 +++-
>  lib/smp_processor_id.c           |    2 +-
>  mm/vmscan.c                      |    2 +-
>  19 files changed, 36 insertions(+), 25 deletions(-)
> 
> 
>

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[patch 00/18] init: Enable might_sleep() and smp_processor_id()  debugging early Thomas Gleixner <tglx@linutronix.de> - 2017-05-14 20:50 +0200
  [patch 09/18] cpufreq/pasemi: Adjust system_state check Thomas Gleixner <tglx@linutronix.de> - 2017-05-14 20:50 +0200
    Re: [patch 09/18] cpufreq/pasemi: Adjust system_state check Viresh Kumar <viresh.kumar@linaro.org> - 2017-05-15 07:30 +0200
      Re: [patch 09/18] cpufreq/pasemi: Adjust system_state check Steven Rostedt <rostedt@goodmis.org> - 2017-05-15 16:40 +0200
  [patch 13/18] extable: Adjust system_state checks Thomas Gleixner <tglx@linutronix.de> - 2017-05-14 20:50 +0200
    Re: [patch 13/18] extable: Adjust system_state checks Steven Rostedt <rostedt@goodmis.org> - 2017-05-15 16:40 +0200
  [patch 08/18] mm: Adjust system_state check Thomas Gleixner <tglx@linutronix.de> - 2017-05-14 20:50 +0200
    Re: [patch 08/18] mm: Adjust system_state check Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-05-15 08:20 +0200
      Re: [patch 08/18] mm: Adjust system_state check Steven Rostedt <rostedt@goodmis.org> - 2017-05-15 16:40 +0200
  [patch 01/18] init: Pin init task to boot cpu initially Thomas Gleixner <tglx@linutronix.de> - 2017-05-14 20:50 +0200
    Re: [patch 01/18] init: Pin init task to boot cpu initially Steven Rostedt <rostedt@goodmis.org> - 2017-05-15 16:20 +0200
  Re: [patch 12/18] async: Adjust system_state checks Arjan van de Ven <arjan@linux.intel.com> - 2017-05-14 20:50 +0200
  [patch 05/18] metag: Adjust system_state check Thomas Gleixner <tglx@linutronix.de> - 2017-05-14 20:50 +0200
  [patch 02/18] arm: Adjust system_state check Thomas Gleixner <tglx@linutronix.de> - 2017-05-14 20:50 +0200
  [patch 18/18] sched: Enable smp_processor_id() checks early Thomas Gleixner <tglx@linutronix.de> - 2017-05-14 20:50 +0200
    Re: [patch 18/18] sched: Enable smp_processor_id() checks early Steven Rostedt <rostedt@goodmis.org> - 2017-05-15 17:20 +0200
      Re: [patch 18/18] sched: Enable smp_processor_id() checks early Thomas Gleixner <tglx@linutronix.de> - 2017-05-15 17:40 +0200
  [patch 12/18] async: Adjust system_state checks Thomas Gleixner <tglx@linutronix.de> - 2017-05-14 20:50 +0200
  Re: [patch 00/18] init: Enable might_sleep() and smp_processor_id()  debugging early Mark Rutland <mark.rutland@arm.com> - 2017-05-15 14:00 +0200

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