linux-hardened/kernel/time
Suresh Siddha f833bab87f clockevent: Prevent dead lock on clockevents_lock
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>
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: "Pallipadi Venkatesh" <venkatesh.pallipadi@intel.com>
Cc: "Brown Len" <len.brown@intel.com>
LKML-Reference: <1250544899.2709.210.camel@sbs-t61.sc.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2009-08-19 18:15:10 +02:00
..
clockevents.c clockevent: Prevent dead lock on clockevents_lock 2009-08-19 18:15:10 +02:00
clocksource.c clocksource: Prevent NULL pointer dereference 2009-07-19 17:15:54 +02:00
jiffies.c clocksource: pass clocksource to read() callback 2009-04-21 13:41:47 -07:00
Kconfig Kconfig: eliminate "def_bool n" constructs 2008-10-16 11:21:31 -07:00
Makefile timecompare: generic infrastructure to map between two time bases 2009-02-15 22:43:32 -08:00
ntp.c time: ntp: fix bug in ntp_update_offset() & do_adjtimex(), fix 2009-02-26 19:39:47 +01:00
tick-broadcast.c clockevent: Prevent dead lock on clockevents_lock 2009-08-19 18:15:10 +02:00
tick-common.c clockevents: prevent endless loop in tick_handle_periodic() 2009-05-02 10:22:27 +02:00
tick-internal.h NOHZ: restart tick device from irq_enter() 2008-10-17 18:13:38 +02:00
tick-oneshot.c clocksource: prevent selection of low resolution clocksourse also for nohz=on 2009-06-13 12:00:26 +02:00
tick-sched.c Merge branch 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-06-20 10:51:44 -07:00
timecompare.c timecompare: generic infrastructure to map between two time bases 2009-02-15 22:43:32 -08:00
timekeeping.c Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6 2009-06-11 09:01:14 +03:00
timer_list.c timers: Drop write permission on /proc/timer_list 2009-08-17 11:47:31 +02:00
timer_stats.c timer stats: Optimize by adding quick check to avoid function calls 2009-06-24 11:15:09 +02:00