[PATCH 3.10 11/43] regmap: debugfs: fix possbile NULL pointer dereference

From: Greg Kroah-Hartman
Date: Mon Oct 27 2014 - 23:52:45 EST


3.10-stable review patch. If anyone has any objections, please let me know.

------------------

From: Xiubo Li <Li.Xiubo@xxxxxxxxxxxxx>

commit 2c98e0c1cc6b8e86f1978286c3d4e0769ee9d733 upstream.

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@xxxxxxxxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/base/regmap/regmap-debugfs.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

--- a/drivers/base/regmap/regmap-debugfs.c
+++ b/drivers/base/regmap/regmap-debugfs.c
@@ -460,16 +460,20 @@ void regmap_debugfs_init(struct regmap *
{
struct rb_node *next;
struct regmap_range_node *range_node;
+ const char *devname = "dummy";

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);


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