From: Heiko Carstens Both smp_call_function() and __smp_call_function_map() access cpu_online_map. Both functions run with preemption disabled which protects for cpus going offline. However new cpus can be added and therefore the cpu_online_map can change unexpectedly. So use the call_lock to protect against changes to the cpu_online_map in start_secondary() and all smp_call_* functions. Signed-off-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- arch/s390/kernel/smp.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) Index: quilt-2.6/arch/s390/kernel/smp.c =================================================================== --- quilt-2.6.orig/arch/s390/kernel/smp.c +++ quilt-2.6/arch/s390/kernel/smp.c @@ -139,7 +139,6 @@ static void __smp_call_function_map(void if (wait) data.finished = CPU_MASK_NONE; - spin_lock(&call_lock); call_data = &data; for_each_cpu_mask(cpu, map) @@ -151,7 +150,6 @@ static void __smp_call_function_map(void if (wait) while (!cpus_equal(map, data.finished)) cpu_relax(); - spin_unlock(&call_lock); out: if (local) { local_irq_disable(); @@ -177,11 +175,11 @@ int smp_call_function(void (*func) (void { cpumask_t map; - preempt_disable(); + spin_lock(&call_lock); map = cpu_online_map; cpu_clear(smp_processor_id(), map); __smp_call_function_map(func, info, nonatomic, wait, map); - preempt_enable(); + spin_unlock(&call_lock); return 0; } EXPORT_SYMBOL(smp_call_function); @@ -202,10 +200,10 @@ EXPORT_SYMBOL(smp_call_function); int smp_call_function_single(int cpu, void (*func) (void *info), void *info, int nonatomic, int wait) { - preempt_disable(); + spin_lock(&call_lock); __smp_call_function_map(func, info, nonatomic, wait, cpumask_of_cpu(cpu)); - preempt_enable(); + spin_unlock(&call_lock); return 0; } EXPORT_SYMBOL(smp_call_function_single); @@ -228,10 +226,10 @@ EXPORT_SYMBOL(smp_call_function_single); int smp_call_function_mask(cpumask_t mask, void (*func)(void *), void *info, int wait) { - preempt_disable(); + spin_lock(&call_lock); cpu_clear(smp_processor_id(), mask); __smp_call_function_map(func, info, 0, wait, mask); - preempt_enable(); + spin_unlock(&call_lock); return 0; } EXPORT_SYMBOL(smp_call_function_mask); @@ -592,7 +590,9 @@ int __cpuinit start_secondary(void *cpuv pfault_init(); /* Mark this cpu as online */ + spin_lock(&call_lock); cpu_set(smp_processor_id(), cpu_online_map); + spin_unlock(&call_lock); /* Switch on interrupts */ local_irq_enable(); /* Print info about this processor */ -- blue skies, Martin. "Reality continues to ruin my life." - Calvin. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/