1 files changed, 5 insertions, 2 deletions

diff --git a/arch/powerpc/kernel/irq.c b/arch/powerpc/kernel/irq.c
index ac4d29119f3e..6cb3fcd7fc37 100644
--- a/arch/powerpc/kernel/irq.c
+++ b/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.