linux/drivers/base
Rafael J. Wysocki a9306a6363 PM / runtime: Avoid false-positive warnings from might_sleep_if()
The might_sleep_if() assertions in __pm_runtime_idle(),
__pm_runtime_suspend() and __pm_runtime_resume() may generate
false-positive warnings in some situations.  For example, that
happens if a nested pm_runtime_get_sync()/pm_runtime_put() pair
is executed with disabled interrupts within an outer
pm_runtime_get_sync()/pm_runtime_put() section for the same device.
[Generally, pm_runtime_get_sync() may sleep, so it should not be
called with disabled interrupts, but in this particular case the
previous pm_runtime_get_sync() guarantees that the device will not
be suspended, so the inner pm_runtime_get_sync() will return
immediately after incrementing the device's usage counter.]

That started to happen in the i915 driver in 4.10-rc, leading to
the following splat:

 BUG: sleeping function called from invalid context at drivers/base/power/runtime.c:1032
 in_atomic(): 1, irqs_disabled(): 0, pid: 1500, name: Xorg
 1 lock held by Xorg/1500:
  #0:  (&dev->struct_mutex){+.+.+.}, at:
  [<ffffffffa0680c13>] i915_mutex_lock_interruptible+0x43/0x140 [i915]
 CPU: 0 PID: 1500 Comm: Xorg Not tainted
 Call Trace:
  dump_stack+0x85/0xc2
  ___might_sleep+0x196/0x260
  __might_sleep+0x53/0xb0
  __pm_runtime_resume+0x7a/0x90
  intel_runtime_pm_get+0x25/0x90 [i915]
  aliasing_gtt_bind_vma+0xaa/0xf0 [i915]
  i915_vma_bind+0xaf/0x1e0 [i915]
  i915_gem_execbuffer_relocate_entry+0x513/0x6f0 [i915]
  i915_gem_execbuffer_relocate_vma.isra.34+0x188/0x250 [i915]
  ? trace_hardirqs_on+0xd/0x10
  ? i915_gem_execbuffer_reserve_vma.isra.31+0x152/0x1f0 [i915]
  ? i915_gem_execbuffer_reserve.isra.32+0x372/0x3a0 [i915]
  i915_gem_do_execbuffer.isra.38+0xa70/0x1a40 [i915]
  ? __might_fault+0x4e/0xb0
  i915_gem_execbuffer2+0xc5/0x260 [i915]
  ? __might_fault+0x4e/0xb0
  drm_ioctl+0x206/0x450 [drm]
  ? i915_gem_execbuffer+0x340/0x340 [i915]
  ? __fget+0x5/0x200
  do_vfs_ioctl+0x91/0x6f0
  ? __fget+0x111/0x200
  ? __fget+0x5/0x200
  SyS_ioctl+0x79/0x90
  entry_SYSCALL_64_fastpath+0x23/0xc6

even though the code triggering it is correct.

Unfortunately, the might_sleep_if() assertions in question are
too coarse-grained to cover such cases correctly, so make them
a bit less sensitive in order to avoid the false-positives.

Reported-and-tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2017-02-04 00:44:36 +01:00
..
power PM / runtime: Avoid false-positive warnings from might_sleep_if() 2017-02-04 00:44:36 +01:00
regmap regmap: cache: Remove unused 'blksize' variable 2016-11-25 13:01:36 +00:00
test driver core: test_async: fix up typo found by 0-day 2016-11-29 22:06:42 +01:00
attribute_container.c attribute_container: Fix typo 2016-08-31 15:13:56 +02:00
base.h Revert "driver core: Add deferred_probe attribute to devices in sysfs" 2017-01-14 14:09:03 +01:00
bus.c driver core: bus: use to_subsys_private and to_device_private_bus 2016-02-09 17:25:27 -08:00
cacheinfo.c Merge branch 'x86-cache-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-12-22 09:25:45 -08:00
class.c driver core: class: add class_groups support 2016-11-29 21:12:12 +01:00
component.c Merge 4.5-rc4 into driver-core-next 2016-02-14 14:29:55 -08:00
container.c
core.c Revert "driver core: Add deferred_probe attribute to devices in sysfs" 2017-01-14 14:09:03 +01:00
cpu.c cpu: clean up register_cpu func 2016-08-31 15:19:55 +02:00
dd.c Revert "driver core: Add deferred_probe attribute to devices in sysfs" 2017-01-14 14:09:03 +01:00
devcoredump.c driver core: devcoredump: convert to use class_groups 2016-11-29 21:12:12 +01:00
devres.c devres: add devm_alloc_percpu() 2016-11-15 22:34:25 -05:00
devtmpfs.c wrappers for ->i_mutex access 2016-01-22 18:04:28 -05:00
dma-coherent.c drivers: dma-coherent: Move spinlock in dma_alloc_from_coherent() 2016-09-28 17:53:16 +02:00
dma-contiguous.c driver core update for 4.4-rc1 2015-11-04 21:50:37 -08:00
dma-mapping.c drivers: base: dma-mapping: Fix typo in dmam_alloc_non_coherent comments 2016-11-30 13:04:53 +01:00
driver.c
firmware_class.c firmware: Correct handling of fw_state_wait() return value 2016-12-08 21:05:54 +01:00
firmware.c
hypervisor.c
init.c
isa.c isa: Call isa_bus_init before dependent ISA bus drivers register 2016-06-17 20:47:11 -07:00
Kconfig Driver core patches for 4.10-rc1 2016-12-13 11:42:18 -08:00
Makefile driver-core: add test module for asynchronous probing 2016-11-10 17:28:16 +01:00
map.c
memory.c memory_hotplug: make zone_can_shift() return a boolean value 2017-01-24 16:26:14 -08:00
module.c base: make module_create_drivers_dir race-free 2016-06-15 19:21:31 -07:00
node.c treewide: replace obsolete _refok by __ref 2016-08-02 17:31:41 -04:00
pinctrl.c driver: base: pinctrl: return error from pinctrl_bind_pins() 2016-09-13 23:02:59 +02:00
platform-msi.c genirq/msi: Add cpumask allocation to alloc_msi_entry 2016-09-14 22:11:08 +02:00
platform.c driver-core: platform: Catch errors from calls to irq_get_irq_data 2016-09-27 12:30:37 +02:00
property.c device property: Add function to search for named child of device 2016-06-26 12:39:03 +01:00
soc.c base: soc: Check for NULL SoC device attributes 2016-11-10 10:10:33 +01:00
syscore.c
topology.c drivers base/topology: Convert to hotplug state machine 2016-11-09 23:45:29 +01:00
transport_class.c