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[IA64] eliminate race condition in smp_flush_tlb_mm

A race condition exists within smp_call_function_many() when called from
smp_flush_tlb_mm().  On rare occasions the cpu_vm_mask can be cleared
while smp_call_function_many is executing, occasionally resulting in a
hung process.

Make a copy of the mask prior to calling smp_call_function_many().

Signed-off-by: Dimitri Sivanich <sivanich@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
master
Dimitri Sivanich 11 years ago
committed by Tony Luck
parent
commit
75c1c91cb9
  1. 13
      arch/ia64/kernel/smp.c

13
arch/ia64/kernel/smp.c

@ -293,6 +293,7 @@ smp_flush_tlb_all (void)
void
smp_flush_tlb_mm (struct mm_struct *mm)
{
cpumask_var_t cpus;
preempt_disable();
/* this happens for the common case of a single-threaded fork(): */
if (likely(mm == current->active_mm && atomic_read(&mm->mm_users) == 1))
@ -301,9 +302,15 @@ smp_flush_tlb_mm (struct mm_struct *mm)
preempt_enable();
return;
}
smp_call_function_many(mm_cpumask(mm),
(void (*)(void *))local_finish_flush_tlb_mm, mm, 1);
if (!alloc_cpumask_var(&cpus, GFP_ATOMIC)) {
smp_call_function((void (*)(void *))local_finish_flush_tlb_mm,
mm, 1);
} else {
cpumask_copy(cpus, mm_cpumask(mm));
smp_call_function_many(cpus,
(void (*)(void *))local_finish_flush_tlb_mm, mm, 1);
free_cpumask_var(cpus);
}
local_irq_disable();
local_finish_flush_tlb_mm(mm);
local_irq_enable();

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