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arm: use clear_tasks_mm_cpumask()

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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@redhat.com>
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Anton Vorontsov 2012-05-31 16:26:22 -07:00 committed by Linus Torvalds
parent cb79295e20
commit 3eaa73bde2
1 changed files with 1 additions and 7 deletions
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8
arch/arm/kernel/smp.c
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@ -109,7 +109,6 @@ 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);
@ -139,12 +138,7 @@ 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;
}