Suresh Siddha 843447c62b clockevent: Prevent dead lock on clockevents_lock ... This is a merge of two mainline commits, intended for stable@kernel.org submission for 2.6.27 kernel. commit f833bab87f and commit 918aae42aa Changelog of both: Currently clockevents_notify() is called with interrupts enabled at some places and interrupts disabled at some other places. This results in a deadlock in this scenario. cpu A holds clockevents_lock in clockevents_notify() with irqs enabled cpu B waits for clockevents_lock in clockevents_notify() with irqs disabled cpu C doing set_mtrr() which will try to rendezvous of all the cpus. This will result in C and A come to the rendezvous point and waiting for B. B is stuck forever waiting for the spinlock and thus not reaching the rendezvous point. Fix the clockevents code so that clockevents_lock is taken with interrupts disabled and thus avoid the above deadlock. Also call lapic_timer_propagate_broadcast() on the destination cpu so that we avoid calling smp_call_function() in the clockevents notifier chain. This issue left us wondering if we need to change the MTRR rendezvous logic to use stop machine logic (instead of smp_call_function) or add a check in spinlock debug code to see if there are other spinlocks which gets taken under both interrupts enabled/disabled conditions. Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> Cc: "Brown Len" <len.brown@intel.com> Cc: stable@kernel.org LKML-Reference: <1250544899.2709.210.camel@sbs-t61.sc.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> I got following warning on ia64 box: In function 'acpi_processor_power_verify': 642: warning: passing argument 2 of 'smp_call_function_single' from incompatible pointer type This smp_call_function_single() was introduced by a commit f833bab87f: The problem is that the lapic_timer_propagate_broadcast() has 2 versions: One is real code that modified in the above commit, and the other is NOP code that used when !ARCH_APICTIMER_STOPS_ON_C3: static void lapic_timer_propagate_broadcast(struct acpi_processor *pr) { } So I got warning because of !ARCH_APICTIMER_STOPS_ON_C3. We really want to do nothing here on !ARCH_APICTIMER_STOPS_ON_C3, so modify lapic_timer_propagate_broadcast() of real version to use smp_call_function_single() in it. Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Acked-by: Suresh Siddha <suresh.b.siddha@intel.com> Signed-off-by: Len Brown <len.brown@intel.com> Signed-off-by: Thomas Renninger <trenn@suse.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>		2010-05-26 14:27:07 -07:00
..
clockevents.c	clockevent: Prevent dead lock on clockevents_lock	2010-05-26 14:27:07 -07:00
clocksource.c	Merge branch 'cpus4096-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip	2008-07-23 18:37:44 -07:00
jiffies.c	[PATCH] fix jiffies clocksource inittime	2007-04-04 21:12:47 -07:00
Kconfig	clockevents: Allow build w/o run-tine usage for migration purposes	2007-10-12 23:04:05 +02:00
Makefile	clockevents: Allow build w/o run-tine usage for migration purposes	2007-10-12 23:04:05 +02:00
ntp.c	ntp: fix calculation of the next jiffie to trigger RTC sync	2008-09-06 15:31:48 +02:00
tick-broadcast.c	clockevent: Prevent dead lock on clockevents_lock	2010-05-26 14:27:07 -07:00
tick-common.c	clockevents: prevent endless loop in tick_handle_periodic()	2009-05-08 14:54:36 -07:00
tick-internal.h	timers: fix build error in !oneshot case	2008-09-23 12:57:00 +02:00
tick-oneshot.c	clockevents: remove WARN_ON which was used to gather information	2008-09-09 22:20:01 +02:00
tick-sched.c	printk: robustify printk	2009-11-09 16:52:43 -08:00
timekeeping.c	time: catch xtime_nsec underflows and fix them	2009-10-12 11:33:23 -07:00
timer_list.c	kernel: use non-racy method for proc entries creation	2008-04-29 08:06:22 -07:00
timer_stats.c	kernel: use non-racy method for proc entries creation	2008-04-29 08:06:22 -07:00