diff options
| author | Suresh Siddha <suresh.b.siddha@intel.com> | 2009-08-18 01:34:59 +0400 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2009-08-19 20:15:10 +0400 |
| commit | f833bab87fca5c3ce13778421b1365845843b976 (patch) | |
| tree | 020c3e6a70dba34544c963c34647b605035be8fb /drivers/acpi | |
| parent | de809347aeef0a68c04576c464414d0e4dce59fc (diff) | |
| download | linux-f833bab87fca5c3ce13778421b1365845843b976.tar.xz | |
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>
Diffstat (limited to 'drivers/acpi')
| -rw-r--r-- | drivers/acpi/processor_idle.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index 0efa59e7e3af..66393d5c4c7c 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -162,8 +162,9 @@ static void lapic_timer_check_state(int state, struct acpi_processor *pr, pr->power.timer_broadcast_on_state = state; } -static void lapic_timer_propagate_broadcast(struct acpi_processor *pr) +static void lapic_timer_propagate_broadcast(void *arg) { + struct acpi_processor *pr = (struct acpi_processor *) arg; unsigned long reason; reason = pr->power.timer_broadcast_on_state < INT_MAX ? @@ -635,7 +636,8 @@ static int acpi_processor_power_verify(struct acpi_processor *pr) working++; } - lapic_timer_propagate_broadcast(pr); + smp_call_function_single(pr->id, lapic_timer_propagate_broadcast, + pr, 1); return (working); } |