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

diff --git a/drivers/base/regmap/regmap-debugfs.c b/drivers/base/regmap/regmap-debugfs.c
index 45d812c..bdd8870 100644 (file)
--- 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);