Paul E. McKenney 778935778c PM / runtime: Use _rcuidle for runtime suspend tracepoints ... Further testing with false negatives suppressed by commit 293e2421fe ("rcu: Remove superfluous versions of rcu_read_lock_sched_held()") identified a few more unprotected uses of RCU from the idle loop. Because RCU actively ignores idle-loop code (for energy-efficiency reasons, among other things), using RCU from the idle loop can result in too-short grace periods, in turn resulting in arbitrary misbehavior. The affected function is rpm_suspend(). The resulting lockdep-RCU splat is as follows: ------------------------------------------------------------------------ Warning from omap3 =============================== [ INFO: suspicious RCU usage. ] 4.6.0-rc5-next-20160426+ #1112 Not tainted ------------------------------- include/trace/events/rpm.h:63 suspicious rcu_dereference_check() usage! other info that might help us debug this: RCU used illegally from idle CPU! rcu_scheduler_active = 1, debug_locks = 0 RCU used illegally from extended quiescent state! 1 lock held by swapper/0/0: #0: (&(&dev->power.lock)->rlock){-.-...}, at: [<c052ee24>] __pm_runtime_suspend+0x54/0x84 stack backtrace: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.6.0-rc5-next-20160426+ #1112 Hardware name: Generic OMAP36xx (Flattened Device Tree) [<c0110308>] (unwind_backtrace) from [<c010c3a8>] (show_stack+0x10/0x14) [<c010c3a8>] (show_stack) from [<c047fec8>] (dump_stack+0xb0/0xe4) [<c047fec8>] (dump_stack) from [<c052d7b4>] (rpm_suspend+0x604/0x7e4) [<c052d7b4>] (rpm_suspend) from [<c052ee34>] (__pm_runtime_suspend+0x64/0x84) [<c052ee34>] (__pm_runtime_suspend) from [<c04bf3bc>] (omap2_gpio_prepare_for_idle+0x5c/0x70) [<c04bf3bc>] (omap2_gpio_prepare_for_idle) from [<c01255e8>] (omap_sram_idle+0x140/0x244) [<c01255e8>] (omap_sram_idle) from [<c0126b48>] (omap3_enter_idle_bm+0xfc/0x1ec) [<c0126b48>] (omap3_enter_idle_bm) from [<c0601db8>] (cpuidle_enter_state+0x80/0x3d4) [<c0601db8>] (cpuidle_enter_state) from [<c0183c74>] (cpu_startup_entry+0x198/0x3a0) [<c0183c74>] (cpu_startup_entry) from [<c0b00c0c>] (start_kernel+0x354/0x3c8) [<c0b00c0c>] (start_kernel) from [<8000807c>] (0x8000807c) ------------------------------------------------------------------------ Reported-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Tested-by: Tony Lindgren <tony@atomide.com> Tested-by: Guenter Roeck <linux@roeck-us.net> [ rjw: Subject ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>		2016-09-16 02:59:58 +02:00
..
power	PM / runtime: Use _rcuidle for runtime suspend tracepoints	2016-09-16 02:59:58 +02:00
regmap	Merge remote-tracking branch 'regmap/fix/rbtree' into regmap-linus	2016-09-03 12:10:09 +01:00
attribute_container.c
base.h
bus.c
cacheinfo.c
class.c
component.c
container.c
core.c
cpu.c
dd.c	Revert "base: dd: don't remove driver_data in -EPROBE_DEFER case"	2016-05-03 08:06:06 -07:00
devcoredump.c	devcoredump: add scatterlist support	2016-04-15 11:20:32 -07:00
devres.c
devtmpfs.c
dma-coherent.c
dma-contiguous.c
dma-mapping.c
driver.c
firmware_class.c	firmware: support loading into a pre-allocated buffer	2016-08-02 19:35:10 -04:00
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
Makefile	isa: Allow ISA-style drivers on modern systems	2016-06-17 20:21:12 -07:00
map.c
memory.c	memory-hotplug: use zone_can_shift() for sysfs valid_zones attribute	2016-07-26 16:19:19 -07:00
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
platform-msi.c
platform.c	device property: don't bother the drivers with struct property_set	2016-04-09 03:10:50 +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
syscore.c
topology.c	topology/sysfs: provide drawer id and siblings attributes	2016-06-13 15:58:27 +02:00
transport_class.c