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author | Suresh Siddha <suresh.b.siddha@intel.com> | 2009-08-17 14:34:59 -0700 |
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committer | Thomas Gleixner <tglx@linutronix.de> | 2009-08-19 18:15:10 +0200 |
commit | f833bab87fca5c3ce13778421b1365845843b976 (patch) | |
tree | 020c3e6a70dba34544c963c34647b605035be8fb /arch | |
parent | de809347aeef0a68c04576c464414d0e4dce59fc (diff) | |
download | linux-f833bab87fca5c3ce13778421b1365845843b976.tar.gz linux-f833bab87fca5c3ce13778421b1365845843b976.tar.bz2 linux-f833bab87fca5c3ce13778421b1365845843b976.zip |
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 'arch')
-rw-r--r-- | arch/x86/kernel/process.c | 6 |
1 files changed, 1 insertions, 5 deletions
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 994dd6a4a2a0..071166a4ba83 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -519,16 +519,12 @@ static void c1e_idle(void) if (!cpumask_test_cpu(cpu, c1e_mask)) { cpumask_set_cpu(cpu, c1e_mask); /* - * Force broadcast so ACPI can not interfere. Needs - * to run with interrupts enabled as it uses - * smp_function_call. + * Force broadcast so ACPI can not interfere. */ - local_irq_enable(); clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_FORCE, &cpu); printk(KERN_INFO "Switch to broadcast mode on CPU%d\n", cpu); - local_irq_disable(); } clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu); |