Checking for process->mm is not enough because process' main
thread may exit or detach its mm via use_mm(), but other threads
may still have a valid mm.
To fix this we would need to use find_lock_task_mm(), which would
walk up all threads and returns an appropriate task (with task
lock held).
clear_tasks_mm_cpumask() has this issue fixed, so let's use it.
Suggested-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Anton Vorontsov <anton.vorontsov@xxxxxxxxxx>
---
arch/arm/kernel/smp.c | 8 +-------
1 file changed, 1 insertion(+), 7 deletions(-)
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index addbbe8..e824ee4 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -130,7 +130,6 @@ static void percpu_timer_stop(void);
int __cpu_disable(void)
{
unsigned int cpu = smp_processor_id();
- struct task_struct *p;
int ret;
ret = platform_cpu_disable(cpu);
@@ -160,12 +159,7 @@ int __cpu_disable(void)
flush_cache_all();
local_flush_tlb_all();
- read_lock(&tasklist_lock);
- for_each_process(p) {
- if (p->mm)
- cpumask_clear_cpu(cpu, mm_cpumask(p->mm));
- }
- read_unlock(&tasklist_lock);
+ clear_tasks_mm_cpumask(cpu);
return 0;
}
--
1.7.9.2
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