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  1. 08 Feb, 2018 3 commits
  3. 07 Feb, 2018 3 commits
  5. 05 Feb, 2018 1 commit
    • Bo Yan's avatar
      cpufreq: Skip cpufreq resume if it's not suspended · 703cbaa6
      Bo Yan authored 
      cpufreq_resume can be called even without preceding cpufreq_suspend.
This can happen in following scenario:

    suspend_devices_and_enter
       --> dpm_suspend_start
          --> dpm_prepare
              --> device_prepare : this function errors out
          --> dpm_suspend: this is skipped due to dpm_prepare failure
                           this means cpufreq_suspend is skipped over
       --> goto Recover_platform, due to previous error
       --> goto Resume_devices
       --> dpm_resume_end
           --> dpm_resume
               --> cpufreq_resume

In case schedutil is used as frequency governor, cpufreq_resume will
eventually call sugov_start, which does following:

    memset(sg_cpu, 0, sizeof(*sg_cpu));
    ....

This effectively erases function pointer for frequency update, causing
crash later on. The function pointer would have been set correctly if
subsequent cpufreq_add_update_util_hook runs successfully, but that
function returns earlier because cpufreq_suspend was not called:

    if (WARN_ON(per_cpu(cpufreq_update_util_data, cpu)))
		return;

The fix is to check cpufreq_suspended first, if it's false, that means
cpufreq_suspend was not called in the first place, so do not resume
cpufreq.
Signed-off-by: default avatarBo Yan <byan@nvidia.com>
Acked-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
[ rjw: Dropped printing a message ]
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
      703cbaa6
  7. 29 Jan, 2018 3 commits
    • Linus Torvalds's avatar
      Merge tag 'pm-4.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm · 7f3fdd40
      Linus Torvalds authored 
      Pull power management updates from Rafael Wysocki:
 "This includes some infrastructure changes in the PM core, mostly
  related to integration between runtime PM and system-wide suspend and
  hibernation, plus some driver changes depending on them and fixes for
  issues in that area which have become quite apparent recently.

  Also included are changes making more x86-based systems use the Low
  Power Sleep S0 _DSM interface by default, which turned out to be
  necessary to handle power button wakeups from suspend-to-idle on
  Surface Pro3.

  On the cpufreq front we have fixes and cleanups in the core, some new
  hardware support, driver updates and the removal of some unused code
  from the CPU cooling thermal driver.

  Apart from this, the Operating Performance Points (OPP) framework is
  prepared to be used with power domains in the future and there is a
  usual bunch of assorted fixes and cleanups.

  Specifics:

   - Define a PM driver flag allowing drivers to request that their
     devices be left in suspend after system-wide transitions to the
     working state if possible and add support for it to the PCI bus
     type and the ACPI PM domain (Rafael Wysocki).

   - Make the PM core carry out optimizations for devices with driver PM
     flags set in some cases and make a few drivers set those flags
     (Rafael Wysocki).

   - Fix and clean up wrapper routines allowing runtime PM device
     callbacks to be re-used for system-wide PM, change the generic
     power domains (genpd) framework to stop using those routines
     incorrectly and fix up a driver depending on that behavior of genpd
     (Rafael Wysocki, Ulf Hansson, Geert Uytterhoeven).

   - Fix and clean up the PM core's device wakeup framework and
     re-factor system-wide PM core code related to device wakeup
     (Rafael Wysocki, Ulf Hansson, Brian Norris).

   - Make more x86-based systems use the Low Power Sleep S0 _DSM
     interface by default (to fix power button wakeup from
     suspend-to-idle on Surface Pro3) and add a kernel command line
     switch to tell it to ignore the system sleep blacklist in the ACPI
     core (Rafael Wysocki).

   - Fix a race condition related to cpufreq governor module removal and
     clean up the governor management code in the cpufreq core (Rafael
     Wysocki).

   - Drop the unused generic code related to the handling of the static
     power energy usage model in the CPU cooling thermal driver along
     with the corresponding documentation (Viresh Kumar).

   - Add mt2712 support to the Mediatek cpufreq driver (Andrew-sh
     Cheng).

   - Add a new operating point to the imx6ul and imx6q cpufreq drivers
     and switch the latter to using clk_bulk_get() (Anson Huang, Dong
     Aisheng).

   - Add support for multiple regulators to the TI cpufreq driver along
     with a new DT binding related to that and clean up that driver
     somewhat (Dave Gerlach).

   - Fix a powernv cpufreq driver regression leading to incorrect CPU
     frequency reporting, fix that driver to deal with non-continguous
     P-states correctly and clean it up (Gautham Shenoy, Shilpasri
     Bhat).

   - Add support for frequency scaling on Armada 37xx SoCs through the
     generic DT cpufreq driver (Gregory CLEMENT).

   - Fix error code paths in the mvebu cpufreq driver (Gregory CLEMENT).

   - Fix a transition delay setting regression in the longhaul cpufreq
     driver (Viresh Kumar).

   - Add Skylake X (server) support to the intel_pstate cpufreq driver
     and clean up that driver somewhat (Srinivas Pandruvada).

   - Clean up the cpufreq statistics collection code (Viresh Kumar).

   - Drop cluster terminology and dependency on physical_package_id from
     the PSCI driver and drop dependency on arm_big_little from the SCPI
     cpufreq driver (Sudeep Holla).

   - Add support for system-wide suspend and resume to the RAPL power
     capping driver and drop a redundant semicolon from it (Zhen Han,
     Luis de Bethencourt).

   - Make SPI domain validation (in the SCSI SPI transport driver) and
     system-wide suspend mutually exclusive as they rely on the same
     underlying mechanism and cannot be carried out at the same time
     (Bart Van Assche).

   - Fix the computation of the amount of memory to preallocate in the
     hibernation core and clean up one function in there (Rainer Fiebig,
     Kyungsik Lee).

   - Prepare the Operating Performance Points (OPP) framework for being
     used with power domains and clean up one function in it (Viresh
     Kumar, Wei Yongjun).

   - Clean up the generic sysfs interface for device PM (Andy
     Shevchenko).

   - Fix several minor issues in power management frameworks and clean
     them up a bit (Arvind Yadav, Bjorn Andersson, Geert Uytterhoeven,
     Gustavo Silva, Julia Lawall, Luis de Bethencourt, Paul Gortmaker,
     Sergey Senozhatsky, gaurav jindal).

   - Make it easier to disable PM via Kconfig (Mark Brown).

   - Clean up the cpupower and intel_pstate_tracer utilities (Doug
     Smythies, Laura Abbott)"

* tag 'pm-4.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (89 commits)
  PCI / PM: Remove spurious semicolon
  cpufreq: scpi: remove arm_big_little dependency
  drivers: psci: remove cluster terminology and dependency on physical_package_id
  powercap: intel_rapl: Fix trailing semicolon
  dmaengine: rcar-dmac: Make DMAC reinit during system resume explicit
  PM / runtime: Allow no callbacks in pm_runtime_force_suspend|resume()
  PM / hibernate: Drop unused parameter of enough_swap
  PM / runtime: Check ignore_children in pm_runtime_need_not_resume()
  PM / runtime: Rework pm_runtime_force_suspend/resume()
  PM / genpd: Stop/start devices without pm_runtime_force_suspend/resume()
  cpufreq: powernv: Dont assume distinct pstate values for nominal and pmin
  cpufreq: intel_pstate: Add Skylake servers support
  cpufreq: intel_pstate: Replace bxt_funcs with core_funcs
  platform/x86: surfacepro3: Support for wakeup from suspend-to-idle
  ACPI / PM: Use Low Power S0 Idle on more systems
  PM / wakeup: Print warn if device gets enabled as wakeup source during sleep
  PM / domains: Don't skip driver's ->suspend|resume_noirq() callbacks
  PM / core: Propagate wakeup_path status flag in __device_suspend_late()
  PM / core: Re-structure code for clearing the direct_complete flag
  powercap: add suspend and resume mechanism for SOC power limit
  ...
      7f3fdd40
    • Linus Torvalds's avatar
      Merge tag 'sound-4.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound · 1c1f395b
      Linus Torvalds authored 
      Pull sound updates from Takashi Iwai:
 "The major changes in the core API side in this cycle are the still
  on-going ASoC componentization works. Other than that, only few small
  changes such as 20bit PCM format support are found.

  Meanwhile the rest majority of changes are for ASoC drivers:

   - Large cleanups of some of the TI CODEC drivers

   - Continued work on Intel ASoC stuff for new quirks, ACPI GPIO
     handling, Kconfigs and lots of cleanups

   - Refactoring of the Freescale SSI driver, as preliminary work for
     the upcoming changes

   - Work on ST DFSDM driver, including the required IIO patches

   - New drivers for Allwinner A83T, Maxim MAX89373, SocioNext UiniPhier
     EVEA Tempo Semiconductor TSCS42xx and TI PCM816x, TAS5722 and
     TAS6424 devices

   - Removal of dead codes for SN95031 and board drivers

  Last but not least, a few HD-audio and USB-audio quirks are included
  as usual, too"

* tag 'sound-4.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound: (303 commits)
  ALSA: hda - Reduce the suspend time consumption for ALC256
  ASoC: use seq_file to dump the contents of dai_list,platform_list and codec_list
  ASoC: soc-core: add missing EXPORT_SYMBOL_GPL() for snd_soc_rtdcom_lookup
  IIO: ADC: stm32-dfsdm: remove unused variable again
  ASoC: bcm2835: fix hw_params error when device is in prepared state
  ASoC: mxs-sgtl5000: Do not print error on probe deferral
  ASoC: sgtl5000: Do not print error on probe deferral
  ASoC: Intel: remove select on non-existing SND_SOC_INTEL_COMMON
  ALSA: usb-audio: Support changing input on Sound Blaster E1
  ASoC: Intel: remove second duplicated assignment to pointer 'res'
  ALSA: hda/realtek - update ALC215 depop optimize
  ALSA: hda/realtek - Support headset mode for ALC215/ALC285/ALC289
  ALSA: pcm: Fix trailing semicolon
  ASoC: add Component level .read/.write
  ASoC: cx20442: fix regression by adding back .read/.write
  ASoC: uda1380: fix regression by adding back .read/.write
  ASoC: tlv320dac33: fix regression by adding back .read/.write
  ALSA: hda - Use IS_REACHABLE() for dependency on input
  IIO: ADC: stm32-dfsdm: fix static check warning
  IIO: ADC: stm32-dfsdm: code optimization
  ...
      1c1f395b
    • Linus Torvalds's avatar
      Merge tag 'init_task-20180117' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs · 49f9c355
      Linus Torvalds authored 
      Pull init_task initializer cleanups from David Howells:
 "It doesn't seem useful to have the init_task in a header file rather
  than in a normal source file. We could consolidate init_task handling
  instead and expand out various macros.

  Here's a series of patches that consolidate init_task handling:

   (1) Make THREAD_SIZE available to vmlinux.lds for cris, hexagon and
       openrisc.

   (2) Alter the INIT_TASK_DATA linker script macro to set
       init_thread_union and init_stack rather than defining these in C.

       Insert init_task and init_thread_into into the init_stack area in
       the linker script as appropriate to the configuration, with
       different section markers so that they end up correctly ordered.

       We can then get merge ia64's init_task.c into the main one.

       We then have a bunch of single-use INIT_*() macros that seem only
       to be macros because they used to be used per-arch. We can then
       expand these in place of the user and get rid of a few lines and
       a lot of backslashes.

   (3) Expand INIT_TASK() in place.

   (4) Expand in place various small INIT_*() macros that are defined
       conditionally. Expand them and surround them by #if[n]def/#endif
       in the .c file as it takes fewer lines.

   (5) Expand INIT_SIGNALS() and INIT_SIGHAND() in place.

   (6) Expand INIT_STRUCT_PID in place.

  These macros can then be discarded"

* tag 'init_task-20180117' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs:
  Expand INIT_STRUCT_PID and remove
  Expand the INIT_SIGNALS and INIT_SIGHAND macros and remove
  Expand various INIT_* macros and remove
  Expand INIT_TASK() in init/init_task.c and remove
  Construct init thread stack in the linker script rather than by union
  openrisc: Make THREAD_SIZE available to vmlinux.lds
  hexagon: Make THREAD_SIZE available to vmlinux.lds
  cris: Make THREAD_SIZE available to vmlinux.lds
      49f9c355
  9. 28 Jan, 2018 8 commits
  11. 27 Jan, 2018 2 commits
    • Thomas Gleixner's avatar
      hrtimer: Reset hrtimer cpu base proper on CPU hotplug · d5421ea4
      Thomas Gleixner authored 
      The hrtimer interrupt code contains a hang detection and mitigation
mechanism, which prevents that a long delayed hrtimer interrupt causes a
continous retriggering of interrupts which prevent the system from making
progress. If a hang is detected then the timer hardware is programmed with
a certain delay into the future and a flag is set in the hrtimer cpu base
which prevents newly enqueued timers from reprogramming the timer hardware
prior to the chosen delay. The subsequent hrtimer interrupt after the delay
clears the flag and resumes normal operation.

If such a hang happens in the last hrtimer interrupt before a CPU is
unplugged then the hang_detected flag is set and stays that way when the
CPU is plugged in again. At that point the timer hardware is not armed and
it cannot be armed because the hang_detected flag is still active, so
nothing clears that flag. As a consequence the CPU does not receive hrtimer
interrupts and no timers expire on that CPU which results in RCU stalls and
other malfunctions.

Clear the flag along with some other less critical members of the hrtimer
cpu base to ensure starting from a clean state when a CPU is plugged in.

Thanks to Paul, Sebastian and Anna-Maria for their help to get down to the
root cause of that hard to reproduce heisenbug. Once understood it's
trivial and certainly justifies a brown paperbag.

Fixes: 41d2e494 ("hrtimer: Tune hrtimer_interrupt hang logic")
Reported-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Sewior <bigeasy@linutronix.de>
Cc: Anna-Maria Gleixner <anna-maria@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/alpine.DEB.2.20.1801261447590.2067@nanos
      d5421ea4
    • H. Peter Anvin's avatar
      x86: Mark hpa as a "Designated Reviewer" for the time being · 8a95b74d
      H. Peter Anvin authored 
      Due to some unfortunate events, I have not been directly involved in
the x86 kernel patch flow for a while now.  I have also not been able
to ramp back up by now like I had hoped to, and after reviewing what I
will need to work on both internally at Intel and elsewhere in the near
term, it is clear that I am not going to be able to ramp back up until
late 2018 at the very earliest.

It is not acceptable to not recognize that this load is currently
taken by Ingo and Thomas without my direct participation, so I mark
myself as R: (designated reviewer) rather than M: (maintainer) until
further notice.  This is in fact recognizing the de facto situation
for the past few years.

I have obviously no intention of going away, and I will do everything
within my power to improve Linux on x86 and x86 for Linux.  This,
however, puts credit where it is due and reflects a change of focus.

This patch also removes stale entries for portions of the x86
architecture which have not been maintained separately from arch/x86
for a long time.  If there is a reason to re-introduce them then that
can happen later.
Signed-off-by: default avatarH. Peter Anvin <h.peter.anvin@intel.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: Bruce Schlobohm <bruce.schlobohm@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180125195934.5253-1-hpa@zytor.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
      8a95b74d
  13. 26 Jan, 2018 13 commits
  15. 25 Jan, 2018 7 commits
    • Lyude Paul's avatar
      drm/nouveau: Move irq setup/teardown to pci ctor/dtor · 0fd189a9
      Lyude Paul authored 
      For a while we've been having issues with seemingly random interrupts
coming from nvidia cards when resuming them. Originally the fix for this
was thought to be just re-arming the MSI interrupt registers right after
re-allocating our IRQs, however it seems a lot of what we do is both
wrong and not even nessecary.

This was made apparent by what appeared to be a regression in the
mainline kernel that started introducing suspend/resume issues for
nouveau:

        a0c9259d (irq/matrix: Spread interrupts on allocation)

After this commit was introduced, we started getting interrupts from the
GPU before we actually re-allocated our own IRQ (see references below)
and assigned the IRQ handler. Investigating this turned out that the
problem was not with the commit, but the fact that nouveau even
free/allocates it's irqs before and after suspend/resume.

For starters: drivers in the linux kernel haven't had to handle
freeing/re-allocating their IRQs during suspend/resume cycles for quite
a while now. Nouveau seems to be one of the few drivers left that still
does this, despite the fact there's no reason we actually need to since
disabling interrupts from the device side should be enough, as the
kernel is already smart enough to know to disable host-side interrupts
for us before going into suspend. Since we were tearing down our IRQs by
hand however, that means there was a short period during resume where
interrupts could be received before we re-allocated our IRQ which would
lead to us getting an unhandled IRQ. Since we never handle said IRQ and
re-arm the interrupt registers, this would cause us to miss all of the
interrupts from the GPU and cause our init process to start timing out
on anything requiring interrupts.

So, since this whole setup/teardown every suspend/resume cycle is
useless anyway, move irq setup/teardown into the pci subdev's ctor/dtor
functions instead so they're only called at driver load and driver
unload. This should fix most of the issues with pending interrupts on
resume, along with getting suspend/resume for nouveau to work again.

As well, this probably means we can also just remove the msi rearm call
inside nvkm_pci_init(). But since our main focus here is to fix
suspend/resume before 4.15, we'll save that for a later patch.
Signed-off-by: default avatarLyude Paul <lyude@redhat.com>
Cc: Karol Herbst <kherbst@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Mike Galbraith <efault@gmx.de>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarBen Skeggs <bskeggs@redhat.com>
      0fd189a9
    • Nicolas Dichtel's avatar
      net: don't call update_pmtu unconditionally · f15ca723
      Nicolas Dichtel authored 
      Some dst_ops (e.g. md_dst_ops)) doesn't set this handler. It may result to:
"BUG: unable to handle kernel NULL pointer dereference at           (null)"

Let's add a helper to check if update_pmtu is available before calling it.

Fixes: 52a589d5 ("geneve: update skb dst pmtu on tx path")
Fixes: a93bf0ff ("vxlan: update skb dst pmtu on tx path")
CC: Roman Kapl <code@rkapl.cz>
CC: Xin Long <lucien.xin@gmail.com>
Signed-off-by: default avatarNicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      f15ca723
    • Linus Torvalds's avatar
      Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm · 6e20630e
      Linus Torvalds authored 
      Pull KVM fixes from Radim Krčmář:
 "Fix races and a potential use after free in the s390 cmma migration
  code"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: s390: add proper locking for CMMA migration bitmap
      6e20630e
    • Linus Torvalds's avatar
      Merge tag 'for-4.15-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux · 525273fb
      Linus Torvalds authored 
      Pull btrfs fix from David Sterba:
 "It's been reported recently that readdir can list stale entries under
  some conditions. Fix it."

* tag 'for-4.15-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux:
  Btrfs: fix stale entries in readdir
      525273fb
    • Dan Streetman's avatar
      net: tcp: close sock if net namespace is exiting · 4ee806d5
      Dan Streetman authored 
      When a tcp socket is closed, if it detects that its net namespace is
exiting, close immediately and do not wait for FIN sequence.

For normal sockets, a reference is taken to their net namespace, so it will
never exit while the socket is open.  However, kernel sockets do not take a
reference to their net namespace, so it may begin exiting while the kernel
socket is still open.  In this case if the kernel socket is a tcp socket,
it will stay open trying to complete its close sequence.  The sock's dst(s)
hold a reference to their interface, which are all transferred to the
namespace's loopback interface when the real interfaces are taken down.
When the namespace tries to take down its loopback interface, it hangs
waiting for all references to the loopback interface to release, which
results in messages like:

unregister_netdevice: waiting for lo to become free. Usage count = 1

These messages continue until the socket finally times out and closes.
Since the net namespace cleanup holds the net_mutex while calling its
registered pernet callbacks, any new net namespace initialization is
blocked until the current net namespace finishes exiting.

After this change, the tcp socket notices the exiting net namespace, and
closes immediately, releasing its dst(s) and their reference to the
loopback interface, which lets the net namespace continue exiting.

Link: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1711407
Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=97811Signed-off-by: default avatarDan Streetman <ddstreet@canonical.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
      4ee806d5
    • Peter Zijlstra's avatar
      perf/x86: Fix perf,x86,cpuhp deadlock · efe951d3
      Peter Zijlstra authored 
      More lockdep gifts, a 5-way lockup race:

	perf_event_create_kernel_counter()
	  perf_event_alloc()
	    perf_try_init_event()
	      x86_pmu_event_init()
		__x86_pmu_event_init()
		  x86_reserve_hardware()
 #0		    mutex_lock(&pmc_reserve_mutex);
		    reserve_ds_buffer()
 #1		      get_online_cpus()

	perf_event_release_kernel()
	  _free_event()
	    hw_perf_event_destroy()
	      x86_release_hardware()
 #0		mutex_lock(&pmc_reserve_mutex)
		release_ds_buffer()
 #1		  get_online_cpus()

 #1	do_cpu_up()
	  perf_event_init_cpu()
 #2	    mutex_lock(&pmus_lock)
 #3	    mutex_lock(&ctx->mutex)

	sys_perf_event_open()
	  mutex_lock_double()
 #3	    mutex_lock(ctx->mutex)
 #4	    mutex_lock_nested(ctx->mutex, 1);

	perf_try_init_event()
 #4	  mutex_lock_nested(ctx->mutex, 1)
	  x86_pmu_event_init()
	    intel_pmu_hw_config()
	      x86_add_exclusive()
 #0		mutex_lock(&pmc_reserve_mutex)

Fix it by using ordering constructs instead of locking.
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      efe951d3
    • Peter Zijlstra's avatar
      perf/core: Fix ctx::mutex deadlock · 0c7296ca
      Peter Zijlstra authored 
      Lockdep noticed the following 3-way lockup scenario:

	sys_perf_event_open()
	  perf_event_alloc()
	    perf_try_init_event()
 #0	      ctx = perf_event_ctx_lock_nested(1)
	      perf_swevent_init()
		swevent_hlist_get()
 #1		  mutex_lock(&pmus_lock)

	perf_event_init_cpu()
 #1	  mutex_lock(&pmus_lock)
 #2	  mutex_lock(&ctx->mutex)

	sys_perf_event_open()
	  mutex_lock_double()
 #2	   mutex_lock()
 #0	   mutex_lock_nested()

And while we need that perf_event_ctx_lock_nested() for HW PMUs such
that they can iterate the sibling list, trying to match it to the
available counters, the software PMUs need do no such thing. Exclude
them.

In particular the swevent triggers the above invertion, while the
tpevent PMU triggers a more elaborate one through their event_mutex.
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
      0c7296ca
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