diff --git a/arch/powerpc/platforms/powernv/memtrace.c b/arch/powerpc/platforms/powernv/memtrace.c
index 232bf5987f91da424cd2d729dc726501d82fc44b..dd3cc4632b9ae6732d79e774fda50ae0c2171813 100644
--- a/arch/powerpc/platforms/powernv/memtrace.c
+++ b/arch/powerpc/platforms/powernv/memtrace.c
@@ -244,9 +244,11 @@ static int memtrace_online(void)
 		 * we need to online the memory ourselves.
 		 */
 		if (!memhp_auto_online) {
+			lock_device_hotplug();
 			walk_memory_range(PFN_DOWN(ent->start),
 					  PFN_UP(ent->start + ent->size - 1),
 					  NULL, online_mem_block);
+			unlock_device_hotplug();
 		}
 
 		/*