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authorTejun Heo <tj@kernel.org>2009-08-14 15:00:49 +0900
committerTejun Heo <tj@kernel.org>2009-08-14 15:00:49 +0900
commit971f3918a5a8febbbab355079972fb31ee7c0f33 (patch)
treedc7909e934473d6b63460c5aa8d0a37ba62a4f79
parent384be2b18a5f9475eab9ca2bdfa95cc1a04ef59c (diff)
percpu: fix pcpu_reclaim() locking
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>
-rw-r--r--mm/percpu.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/mm/percpu.c b/mm/percpu.c
index 3f9f182f9b44..42ab0024a6ed 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -1181,12 +1181,13 @@ static void pcpu_reclaim(struct work_struct *work)
}
spin_unlock_irq(&pcpu_lock);
- mutex_unlock(&pcpu_alloc_mutex);
list_for_each_entry_safe(chunk, next, &todo, list) {
pcpu_depopulate_chunk(chunk, 0, pcpu_unit_size);
free_pcpu_chunk(chunk);
}
+
+ mutex_unlock(&pcpu_alloc_mutex);
}
/**