lib/radix-tree.c: update the kmemleak stack trace for radix tree allocations

Since radix_tree_preload() stack trace is not always useful for
debugging an actual radix tree memory leak, this patch updates the
kmemleak allocation stack trace in the radix_tree_node_alloc() function.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

lib/radix-tree.c

@@ -27,6 +27,7 @@
 #include <linux/radix-tree.h>
 #include <linux/percpu.h>
 #include <linux/slab.h>
+#include <linux/kmemleak.h>
 #include <linux/notifier.h>
 #include <linux/cpu.h>
 #include <linux/string.h>
@@ -200,6 +201,11 @@ radix_tree_node_alloc(struct radix_tree_root *root)
 			rtp->nodes[rtp->nr - 1] = NULL;
 			rtp->nr--;
 		}
+		/*
+		 * Update the allocation stack trace as this is more useful
+		 * for debugging.
+		 */
+		kmemleak_update_trace(ret);
 	}
 	if (ret == NULL)
 		ret = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask);