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  1. 31 1月, 2019 1 次提交
    • V
      PM-runtime: Fix deadlock with ktime_get() · 15efb47d
      由 Vincent Guittot 提交于 
      A deadlock has been seen when swicthing clocksources which use
PM-runtime.  The call path is:

change_clocksource
    ...
    write_seqcount_begin
    ...
    timekeeping_update
        ...
        sh_cmt_clocksource_enable
            ...
            rpm_resume
                pm_runtime_mark_last_busy
                    ktime_get
                        do
                            read_seqcount_begin
                        while read_seqcount_retry
    ....
    write_seqcount_end

Although we should be safe because we haven't yet changed the
clocksource at that time, we can't do that because of seqcount
protection.

Use ktime_get_mono_fast_ns() instead which is lock safe for such
cases.

With ktime_get_mono_fast_ns, the timestamp is not guaranteed to be
monotonic across an update and as a result can goes backward.
According to update_fast_timekeeper() description: "In the worst
case, this can result is a slightly wrong timestamp (a few
nanoseconds)". For PM-runtime autosuspend, this means only that
the suspend decision may be slightly suboptimal.

Fixes: 8234f673 ("PM-runtime: Switch autosuspend over to using hrtimers")
Reported-by: NBiju Das <biju.das@bp.renesas.com>
Signed-off-by: NVincent Guittot <vincent.guittot@linaro.org>
Reviewed-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
      15efb47d
  3. 22 1月, 2019 1 次提交
  5. 15 1月, 2019 1 次提交
  7. 10 1月, 2019 2 次提交
  9. 05 1月, 2019 1 次提交
    • Q
      drivers/base/platform.c: kmemleak ignore a known leak · 967d3010
      由 Qian Cai 提交于 
      unreferenced object 0xffff808ec6dc5a80 (size 128):
  comm "swapper/0", pid 1, jiffies 4294938063 (age 2560.530s)
  hex dump (first 32 bytes):
    ff ff ff ff 00 00 00 00 6b 6b 6b 6b 6b 6b 6b 6b  ........kkkkkkkk
    6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b  kkkkkkkkkkkkkkkk
  backtrace:
    [<00000000476dcf8c>] kmem_cache_alloc_trace+0x430/0x500
    [<000000004f708d37>] platform_device_register_full+0xbc/0x1e8
    [<000000006c2a7ec7>] acpi_create_platform_device+0x370/0x450
    [<00000000ef135642>] acpi_default_enumeration+0x34/0x78
    [<000000003bd9a052>] acpi_bus_attach+0x2dc/0x3e0
    [<000000003cf4f7f2>] acpi_bus_attach+0x108/0x3e0
    [<000000003cf4f7f2>] acpi_bus_attach+0x108/0x3e0
    [<000000002968643e>] acpi_bus_scan+0xb0/0x110
    [<0000000010dd0bd7>] acpi_scan_init+0x1a8/0x410
    [<00000000965b3c5a>] acpi_init+0x408/0x49c
    [<00000000ed4b9fe2>] do_one_initcall+0x178/0x7f4
    [<00000000a5ac5a74>] kernel_init_freeable+0x9d4/0xa9c
    [<0000000070ea6c15>] kernel_init+0x18/0x138
    [<00000000fb8fff06>] ret_from_fork+0x10/0x1c
    [<0000000041273a0d>] 0xffffffffffffffff

Then, faddr2line pointed out this line,

/*
 * This memory isn't freed when the device is put,
 * I don't have a nice idea for that though.  Conceptually
 * dma_mask in struct device should not be a pointer.
 * See http://thread.gmane.org/gmane.linux.kernel.pci/9081
 */
pdev->dev.dma_mask =
	kmalloc(sizeof(*pdev->dev.dma_mask), GFP_KERNEL);

Since this leak has existed for more than 8 years and it does not
reference other parts of the memory, let kmemleak ignore it, so users
don't need to waste time reporting this in the future.

Link: http://lkml.kernel.org/r/20181206160751.36211-1-cai@gmx.usSigned-off-by: NQian Cai <cai@gmx.us>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J . Wysocki" <rafael.j.wysocki@intel.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      967d3010
  11. 03 1月, 2019 1 次提交
  13. 01 1月, 2019 1 次提交
  15. 29 12月, 2018 2 次提交
  17. 26 12月, 2018 2 次提交
  19. 21 12月, 2018 1 次提交
  21. 20 12月, 2018 5 次提交
  23. 19 12月, 2018 5 次提交
    • D
      sysfs: Disable lockdep for driver bind/unbind files · 4f4b3743
      由 Daniel Vetter 提交于 
      This is the much more correct fix for my earlier attempt at:

https://lkml.org/lkml/2018/12/10/118

Short recap:

- There's not actually a locking issue, it's just lockdep being a bit
  too eager to complain about a possible deadlock.

- Contrary to what I claimed the real problem is recursion on
  kn->count. Greg pointed me at sysfs_break_active_protection(), used
  by the scsi subsystem to allow a sysfs file to unbind itself. That
  would be a real deadlock, which isn't what's happening here. Also,
  breaking the active protection means we'd need to manually handle
  all the lifetime fun.

- With Rafael we discussed the task_work approach, which kinda works,
  but has two downsides: It's a functional change for a lockdep
  annotation issue, and it won't work for the bind file (which needs
  to get the errno from the driver load function back to userspace).

- Greg also asked why this never showed up: To hit this you need to
  unregister a 2nd driver from the unload code of your first driver. I
  guess only gpus do that. The bug has always been there, but only
  with a recent patch series did we add more locks so that lockdep
  built a chain from unbinding the snd-hda driver to the
  acpi_video_unregister call.

Full lockdep splat:

[12301.898799] ============================================
[12301.898805] WARNING: possible recursive locking detected
[12301.898811] 4.20.0-rc7+ #84 Not tainted
[12301.898815] --------------------------------------------
[12301.898821] bash/5297 is trying to acquire lock:
[12301.898826] 00000000f61c6093 (kn->count#39){++++}, at: kernfs_remove_by_name_ns+0x3b/0x80
[12301.898841] but task is already holding lock:
[12301.898847] 000000005f634021 (kn->count#39){++++}, at: kernfs_fop_write+0xdc/0x190
[12301.898856] other info that might help us debug this:
[12301.898862]  Possible unsafe locking scenario:
[12301.898867]        CPU0
[12301.898870]        ----
[12301.898874]   lock(kn->count#39);
[12301.898879]   lock(kn->count#39);
[12301.898883] *** DEADLOCK ***
[12301.898891]  May be due to missing lock nesting notation
[12301.898899] 5 locks held by bash/5297:
[12301.898903]  #0: 00000000cd800e54 (sb_writers#4){.+.+}, at: vfs_write+0x17f/0x1b0
[12301.898915]  #1: 000000000465e7c2 (&of->mutex){+.+.}, at: kernfs_fop_write+0xd3/0x190
[12301.898925]  #2: 000000005f634021 (kn->count#39){++++}, at: kernfs_fop_write+0xdc/0x190
[12301.898936]  #3: 00000000414ef7ac (&dev->mutex){....}, at: device_release_driver_internal+0x34/0x240
[12301.898950]  #4: 000000003218fbdf (register_count_mutex){+.+.}, at: acpi_video_unregister+0xe/0x40
[12301.898960] stack backtrace:
[12301.898968] CPU: 1 PID: 5297 Comm: bash Not tainted 4.20.0-rc7+ #84
[12301.898974] Hardware name: Hewlett-Packard HP EliteBook 8460p/161C, BIOS 68SCF Ver. F.01 03/11/2011
[12301.898982] Call Trace:
[12301.898989]  dump_stack+0x67/0x9b
[12301.898997]  __lock_acquire+0x6ad/0x1410
[12301.899003]  ? kernfs_remove_by_name_ns+0x3b/0x80
[12301.899010]  ? find_held_lock+0x2d/0x90
[12301.899017]  ? mutex_spin_on_owner+0xe4/0x150
[12301.899023]  ? find_held_lock+0x2d/0x90
[12301.899030]  ? lock_acquire+0x90/0x180
[12301.899036]  lock_acquire+0x90/0x180
[12301.899042]  ? kernfs_remove_by_name_ns+0x3b/0x80
[12301.899049]  __kernfs_remove+0x296/0x310
[12301.899055]  ? kernfs_remove_by_name_ns+0x3b/0x80
[12301.899060]  ? kernfs_name_hash+0xd/0x80
[12301.899066]  ? kernfs_find_ns+0x6c/0x100
[12301.899073]  kernfs_remove_by_name_ns+0x3b/0x80
[12301.899080]  bus_remove_driver+0x92/0xa0
[12301.899085]  acpi_video_unregister+0x24/0x40
[12301.899127]  i915_driver_unload+0x42/0x130 [i915]
[12301.899160]  i915_pci_remove+0x19/0x30 [i915]
[12301.899169]  pci_device_remove+0x36/0xb0
[12301.899176]  device_release_driver_internal+0x185/0x240
[12301.899183]  unbind_store+0xaf/0x180
[12301.899189]  kernfs_fop_write+0x104/0x190
[12301.899195]  __vfs_write+0x31/0x180
[12301.899203]  ? rcu_read_lock_sched_held+0x6f/0x80
[12301.899209]  ? rcu_sync_lockdep_assert+0x29/0x50
[12301.899216]  ? __sb_start_write+0x13c/0x1a0
[12301.899221]  ? vfs_write+0x17f/0x1b0
[12301.899227]  vfs_write+0xb9/0x1b0
[12301.899233]  ksys_write+0x50/0xc0
[12301.899239]  do_syscall_64+0x4b/0x180
[12301.899247]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
[12301.899253] RIP: 0033:0x7f452ac7f7a4
[12301.899259] Code: 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 80 00 00 00 00 8b 05 aa f0 2c 00 48 63 ff 85 c0 75 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 f3 c3 66 90 55 53 48 89 d5 48 89 f3 48 83
[12301.899273] RSP: 002b:00007ffceafa6918 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[12301.899282] RAX: ffffffffffffffda RBX: 000000000000000d RCX: 00007f452ac7f7a4
[12301.899288] RDX: 000000000000000d RSI: 00005612a1abf7c0 RDI: 0000000000000001
[12301.899295] RBP: 00005612a1abf7c0 R08: 000000000000000a R09: 00005612a1c46730
[12301.899301] R10: 000000000000000a R11: 0000000000000246 R12: 000000000000000d
[12301.899308] R13: 0000000000000001 R14: 00007f452af4a740 R15: 000000000000000d

Looking around I've noticed that usb and i2c already handle similar
recursion problems, where a sysfs file can unbind the same type of
sysfs somewhere else in the hierarchy. Relevant commits are:

commit 356c05d5
Author: Alan Stern <stern@rowland.harvard.edu>
Date:   Mon May 14 13:30:03 2012 -0400

    sysfs: get rid of some lockdep false positives

commit e9b526fe
Author: Alexander Sverdlin <alexander.sverdlin@nsn.com>
Date:   Fri May 17 14:56:35 2013 +0200

    i2c: suppress lockdep warning on delete_device

Implement the same trick for driver bind/unbind.

v2: Put the macro into bus.c (Greg).
Reviewed-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: Ramalingam C <ramalingam.c@intel.com>
Cc: Arend van Spriel <aspriel@gmail.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Bartosz Golaszewski <brgl@bgdev.pl>
Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: Vivek Gautam <vivek.gautam@codeaurora.org>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      4f4b3743
    • Y
      PM / Domains: remove define_genpd_open_function() and define_genpd_debugfs_fops() · d32dcc6c
      由 Yangtao Li 提交于 
      We already have the DEFINE_SHOW_ATTRIBUTE, There is no need to define
such a macro, so remove define_genpd_open_function and
define_genpd_debugfs_fops.

Convert them to DEFINE_SHOW_ATTRIBUTE.
Signed-off-by: NYangtao Li <tiny.windzz@gmail.com>
Acked-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
      d32dcc6c
    • V
      PM-runtime: Switch autosuspend over to using hrtimers · 8234f673
      由 Vincent Guittot 提交于 
      PM-runtime uses the timer infrastructure for autosuspend. This implies
that the minimum time before autosuspending a device is in the range
of 1 tick included to 2 ticks excluded
 -On arm64 this means between 4ms and 8ms with default jiffies
  configuration
 -And on arm, it is between 10ms and 20ms

These values are quite high for embedded systems which sometimes want
the duration to be in the range of 1 ms.

It is possible to switch autosuspend over to using hrtimers to get
finer granularity for short durations and take advantage of slack to
retain some margins and get long timeouts with minimum wakeups.

On an arm64 platform that uses 1ms for autosuspending timeout of its
GPU, idle power is reduced by 10% with hrtimer.

The latency impact on arm64 hikey octo cores is:
 - mark_last_busy: from 1.11 us to 1.25 us
 - rpm_suspend: from 15.54 us to 15.38 us
[Only the code path of rpm_suspend() that starts hrtimer has been
measured.]

arm64 image (arm64 default defconfig) decreases by around 3KB
with following details:

$ size vmlinux-timer
   text	   data	    bss	    dec	    hex	filename
12034646	6869268	 386840	19290754	1265a82	vmlinux

$ size vmlinux-hrtimer
   text	   data	    bss	    dec	    hex	filename
12030550	6870164	 387032	19287746	1264ec2	vmlinux

The latency impact on arm 32bits snowball dual cores is :
 - mark_last_busy: from 0.31 us usec to 0.77 us
 - rpm_suspend: from 6.83 us to 6.67 usec

The increase of the image for snowball platform that I used for
testing performance impact, is neglictable (244B).

$ size vmlinux-timer
   text	   data	    bss	    dec	    hex	filename
7157961	2119580	 264120	9541661	 91981d	build-ux500/vmlinux

size vmlinux-hrtimer
   text	   data	    bss	    dec	    hex	filename
7157773	21198846	 264248	9541905	 919911	vmlinux-hrtimer

And arm 32bits image (multi_v7_defconfig) increases by around 1.7KB
with following details:

$ size vmlinux-timer
   text	   data	    bss	    dec	    hex	filename
13304443	6803420	 402768	20510631	138f7a7	vmlinux

$ size vmlinux-hrtimer
   text	   data	    bss	    dec	    hex	filename
13304299	6805276	 402768	20512343	138fe57	vmlinux
Signed-off-by: NVincent Guittot <vincent.guittot@linaro.org>
Reviewed-by: NUlf Hansson <ulf.hansson@linaro.org>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
      8234f673
    • R
      driver core: Add missing dev->bus->need_parent_lock checks · e121a833
      由 Rafael J. Wysocki 提交于 
      __device_release_driver() has to check dev->bus->need_parent_lock
before dropping the parent lock and acquiring it again as it may
attempt to drop a lock that hasn't been acquired or lock a device
that shouldn't be locked and create a lock imbalance.

Fixes: 8c97a46a (driver core: hold dev's parent lock when needed)
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: stable <stable@vger.kernel.org>
Reviewed-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
      e121a833
    • M
      device property: fix fwnode_graph_get_next_endpoint() documentation · f569da8c
      由 Marco Felsch 提交于 
      Sync documentation with code.

Fixes: 07bb80d4 (device property: Add support for remote endpoints)
Signed-off-by: NMarco Felsch <m.felsch@pengutronix.de>
Acked-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NRafael J. Wysocki <rafael.j.wysocki@intel.com>
      f569da8c
  25. 18 12月, 2018 2 次提交
  27. 14 12月, 2018 7 次提交
  29. 13 12月, 2018 1 次提交
    • M
      platform-msi: Free descriptors in platform_msi_domain_free() · 81b1e6e6
      由 Miquel Raynal 提交于 
      Since the addition of platform MSI support, there were two helpers
supposed to allocate/free IRQs for a device:

    platform_msi_domain_alloc_irqs()
    platform_msi_domain_free_irqs()

In these helpers, IRQ descriptors are allocated in the "alloc" routine
while they are freed in the "free" one.

Later, two other helpers have been added to handle IRQ domains on top
of MSI domains:

    platform_msi_domain_alloc()
    platform_msi_domain_free()

Seen from the outside, the logic is pretty close with the former
helpers and people used it with the same logic as before: a
platform_msi_domain_alloc() call should be balanced with a
platform_msi_domain_free() call. While this is probably what was
intended to do, the platform_msi_domain_free() does not remove/free
the IRQ descriptor(s) created/inserted in
platform_msi_domain_alloc().

One effect of such situation is that removing a module that requested
an IRQ will let one orphaned IRQ descriptor (with an allocated MSI
entry) in the device descriptors list. Next time the module will be
inserted back, one will observe that the allocation will happen twice
in the MSI domain, one time for the remaining descriptor, one time for
the new one. It also has the side effect to quickly overshoot the
maximum number of allocated MSI and then prevent any module requesting
an interrupt in the same domain to be inserted anymore.

This situation has been met with loops of insertion/removal of the
mvpp2.ko module (requesting 15 MSIs each time).

Fixes: 552c494a ("platform-msi: Allow creation of a MSI-based stacked irq domain")
Cc: stable@vger.kernel.org
Signed-off-by: NMiquel Raynal <miquel.raynal@bootlin.com>
Signed-off-by: NMarc Zyngier <marc.zyngier@arm.com>
      81b1e6e6
  31. 11 12月, 2018 2 次提交
  33. 06 12月, 2018 5 次提交