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Paul E. McKenney 0b9a29add4 arm: Use _rcuidle tracepoint to allow use from idle 
Testing on ARM encountered the following pair of lockdep-RCU splats:

------------------------------------------------------------------------

===============================
[ INFO: suspicious RCU usage. ]
4.6.0-rc4-next-20160422 #1 Not tainted
-------------------------------
include/trace/events/power.h:328 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!
no locks held by swapper/0/0.

stack backtrace:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.6.0-rc4-next-20160422 #1
Hardware name: Generic OMAP3-GP (Flattened Device Tree)
[<c010f55c>] (unwind_backtrace) from [<c010b64c>] (show_stack+0x10/0x14)
[<c010b64c>] (show_stack) from [<c047acbc>] (dump_stack+0xa8/0xe0)
[<c047acbc>] (dump_stack) from [<c012bc10>] (pwrdm_set_next_pwrst+0xf8/0x1cc)
[<c012bc10>] (pwrdm_set_next_pwrst) from [<c01269fc>] (omap3_enter_idle_bm+0x1b8/0x1e8)
[<c01269fc>] (omap3_enter_idle_bm) from [<c05fa0b8>] (cpuidle_enter_state+0x84/0x408)
[<c05fa0b8>] (cpuidle_enter_state) from [<c0182c1c>] (cpu_startup_entry+0x1c8/0x3f0)
[<c0182c1c>] (cpu_startup_entry) from [<c0b00c20>] (start_kernel+0x354/0x3cc)

------------------------------------------------------------------------

[<c010f55c>] (unwind_backtrace) from [<c010b64c>] (show_stack+0x10/0x14)
[<c010b64c>] (show_stack) from [<c047ac3c>] (dump_stack+0xa8/0xe0)
[<c047ac3c>] (dump_stack) from [<c012c340>] (_pwrdm_state_switch+0x188/0x32c)
[<c012c340>] (_pwrdm_state_switch) from [<c012c4f0>] (_pwrdm_post_transition_cb+0xc/0x14)
[<c012c4f0>] (_pwrdm_post_transition_cb) from [<c012ba74>] (pwrdm_for_each+0x30/0x5c)
[<c012ba74>] (pwrdm_for_each) from [<c012c72c>] (pwrdm_post_transition+0x24/0x30)
[<c012c72c>] (pwrdm_post_transition) from [<c012548c>] (omap_sram_idle+0xfc/0x240)
[<c012548c>] (omap_sram_idle) from [<c0126934>] (omap3_enter_idle_bm+0xf0/0x1e8)
[<c0126934>] (omap3_enter_idle_bm) from [<c05fa038>] (cpuidle_enter_state+0x84/0x408)
[<c05fa038>] (cpuidle_enter_state) from [<c0182b90>] (cpu_startup_entry+0x1c8/0x3f0)
[<c0182b90>] (cpu_startup_entry) from [<c0b00c20>] (start_kernel+0x354/0x3cc)

------------------------------------------------------------------------

These are caused by event tracing from the idle loop, and they were
exposed by commit 293e2421fe ("rcu: Remove superfluous versions of
rcu_read_lock_sched_held()"), which suppressed some false negatives.
The current commit therefore adds the _rcuidle suffix to make RCU aware
of this implicit use of RCU by event tracing, thus preventing both splats.

Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Tony Lindgren <tony@atomide.com>
Cc: Russell King <linux@arm.linux.org.uk>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Cc: <linux-omap@vger.kernel.org>
Cc: <linux-arm-kernel@lists.infradead.org>
 		2016-04-29 13:29:02 -07:00
..
alpha alpha/extable: use generic search and sort routines 2016-03-22 15:36:02 -07:00
arc asm-generic changes for 4.6 2016-03-24 23:13:48 -07:00
arm arm: Use _rcuidle tracepoint to allow use from idle 2016-04-29 13:29:02 -07:00
arm64 arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections 2016-03-25 16:37:42 -07:00
avr32 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2016-03-19 10:05:34 -07:00
blackfin arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections 2016-03-25 16:37:42 -07:00
c6x arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections 2016-03-25 16:37:42 -07:00
cris Merge branch 'mm-pkeys-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-03-20 19:08:56 -07:00
frv asm-generic changes for 4.6 2016-03-24 23:13:48 -07:00
h8300 h8300: switch EARLYCON 2016-03-25 01:45:19 +09:00
hexagon Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2016-03-19 10:05:34 -07:00
ia64 [IA64] Enable preadv2 and pwritev2 syscalls for ia64 2016-03-25 14:37:32 -07:00
m32r Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2016-03-19 10:05:34 -07:00
m68k asm-generic changes for 4.6 2016-03-24 23:13:48 -07:00
metag arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections 2016-03-25 16:37:42 -07:00
microblaze arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections 2016-03-25 16:37:42 -07:00
mips arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections 2016-03-25 16:37:42 -07:00
mn10300 Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2016-03-19 10:05:34 -07:00
nios2 arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections 2016-03-25 16:37:42 -07:00
openrisc arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections 2016-03-25 16:37:42 -07:00
parisc arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections 2016-03-25 16:37:42 -07:00
powerpc arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections 2016-03-25 16:37:42 -07:00
s390 arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections 2016-03-25 16:37:42 -07:00
score Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2016-03-19 10:05:34 -07:00
sh arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections 2016-03-25 16:37:42 -07:00
sparc arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections 2016-03-25 16:37:42 -07:00
tile arch, ftrace: for KASAN put hard/soft IRQ entries into separate sections 2016-03-25 16:37:42 -07:00
um fs/coredump: prevent fsuid=0 dumps into user-controlled directories 2016-03-22 15:36:02 -07:00
unicore32 Merge branch 'mm-pkeys-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2016-03-20 19:08:56 -07:00
x86 mm, kasan: stackdepot implementation. Enable stackdepot for SLAB 2016-03-25 16:37:42 -07:00
xtensa Xtensa improvements for 4.6: 2016-03-20 12:22:07 -07:00
.gitignore
…
Kconfig objtool: Add CONFIG_STACK_VALIDATION option 2016-02-29 08:35:13 +01:00