regmap: debugfs: fix possbile NULL pointer dereference

If 'map->dev' is NULL and there will lead dev_name() to be NULL pointer
dereference. So before dev_name(), we need to have check of the map->dev
pionter.

We also should make sure that the 'name' pointer shouldn't be NULL for
debugfs_create_dir(). So here using one default "dummy" debugfs name when
the 'name' pointer and 'map->dev' are both NULL.

Signed-off-by: Xiubo Li <Li.Xiubo@freescale.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org

1 files changed, 6 insertions, 2 deletions

diff --git a/drivers/base/regmap/regmap-debugfs.c b/drivers/base/regmap/regmap-debugfs.c
index 45d812c0ea77..bdd88708e4d6 100644
--- a/drivers/base/regmap/regmap-debugfs.c
+++ b/drivers/base/regmap/regmap-debugfs.c
@@ -473,6 +473,7 @@ void regmap_debugfs_init(struct regmap *map, const char *name)
 {
         struct rb_node *next;
         struct regmap_range_node *range_node;
+        const char *devname = "dummy";
 
         /* If we don't have the debugfs root yet, postpone init */
         if (!regmap_debugfs_root) {
@@ -491,12 +492,15 @@ void regmap_debugfs_init(struct regmap *map, const char *name)
         INIT_LIST_HEAD(&map->debugfs_off_cache);
         mutex_init(&map->cache_lock);
 
+        if (map->dev)
+                devname = dev_name(map->dev);
+
         if (name) {
                 map->debugfs_name = kasprintf(GFP_KERNEL, "%s-%s",
-                                              dev_name(map->dev), name);
+                                              devname, name);
                 name = map->debugfs_name;
         } else {
-                name = dev_name(map->dev);
+                name = devname;
         }
 
         map->debugfs = debugfs_create_dir(name, regmap_debugfs_root);