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percpu: fix pcpu_reclaim() locking

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pcpu_reclaim() calls pcpu_depopulate_chunk() which makes use of pages
array and bitmap returned by pcpu_get_pages_and_bitmap() and thus
should be called under pcpu_alloc_mutex.  pcpu_reclaim() released the
mutex before calling depopulate leading to double free and other
strange problems caused by the unexpected concurrent usages of pages
array and bitmap.  Fix it.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
This commit is contained in:
Tejun Heo 2009-08-14 15:00:49 +09:00
parent 384be2b18a
commit 971f3918a5
1 changed files with 2 additions and 1 deletions
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3
mm/percpu.c
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@ -1181,12 +1181,13 @@ static void pcpu_reclaim(struct work_struct *work)
} }
spin_unlock_irq(&pcpu_lock); spin_unlock_irq(&pcpu_lock);
mutex_unlock(&pcpu_alloc_mutex);
list_for_each_entry_safe(chunk, next, &todo, list) { list_for_each_entry_safe(chunk, next, &todo, list) {
pcpu_depopulate_chunk(chunk, 0, pcpu_unit_size); pcpu_depopulate_chunk(chunk, 0, pcpu_unit_size);
free_pcpu_chunk(chunk); free_pcpu_chunk(chunk);
} }
mutex_unlock(&pcpu_alloc_mutex);
} }
/** /**