[PATCH] dmapools: protect page_list walk in show_pools()

From: Thomas Gleixner
Date: Tue Jun 23 2009 - 10:41:42 EST

show_pools() walks the page_list of a pool w/o protection against the
list modifications in alloc/free. Take pool->lock to avoid stomping
into nirvana.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
diff --git a/mm/dmapool.c b/mm/dmapool.c
index b1f0885..3df0637 100644
--- a/mm/dmapool.c
+++ b/mm/dmapool.c
@@ -86,10 +86,12 @@ show_pools(struct device *dev, struct device_attribute *attr, char *buf)
unsigned pages = 0;
unsigned blocks = 0;

+ spin_lock_irq(&pool->lock);
list_for_each_entry(page, &pool->page_list, page_list) {
blocks += page->in_use;
+ spin_unlock_irq(&pool->lock);

/* per-pool info, no real statistics yet */
temp = scnprintf(next, size, "%-16s %4u %4Zu %4Zu %2u\n",

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