diff --git a/[refs] b/[refs]
index e08dc5957e67..00ea6305fa71 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 2e455257d143f54b44701e947a092d513889d01c
+refs/heads/master: 9b7882515864117d0015a3484c0ba0eee6713de9
diff --git a/trunk/arch/powerpc/kernel/irq.c b/trunk/arch/powerpc/kernel/irq.c
index ac4d29119f3e..6cb3fcd7fc37 100644
--- a/trunk/arch/powerpc/kernel/irq.c
+++ b/trunk/arch/powerpc/kernel/irq.c
@@ -893,10 +893,13 @@ unsigned int irq_radix_revmap_lookup(struct irq_host *host,
 		return irq_find_mapping(host, hwirq);
 
 	/*
-	 * No rcu_read_lock(ing) needed, the ptr returned can't go under us
-	 * as it's referencing an entry in the static irq_map table.
+	 * The ptr returned references the static global irq_map.
+	 * but freeing an irq can delete nodes along the path to
+	 * do the lookup via call_rcu.
 	 */
+	rcu_read_lock();
 	ptr = radix_tree_lookup(&host->revmap_data.tree, hwirq);
+	rcu_read_unlock();
 
 	/*
 	 * If found in radix tree, then fine.