[PATCH v4] nvdimm: btt_devs: fix a NULL pointer dereference

[Aditya Pakki]

In case kmemdup fails, the fix releases resources and returns to
avoid the NULL pointer dereference.

Signed-off-by: Aditya Pakki <pakki...@umn.edu>

---
v3: Move kfree(nd_btt) to goto block.
v2: Replace incorrect kfree with ida_simple_remove, suggested by
Johannes Thumshirn
v1: Free nd_btt->id in case of failure and avoid double free, suggested
by Dan Williams
---
 drivers/nvdimm/btt_devs.c | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/nvdimm/btt_devs.c b/drivers/nvdimm/btt_devs.c
index b72a303176c7..9486acc08402 100644
--- a/drivers/nvdimm/btt_devs.c
+++ b/drivers/nvdimm/btt_devs.c
@@ -198,14 +198,15 @@ static struct device *__nd_btt_create(struct nd_region 
*nd_region,
                return NULL;
 
        nd_btt->id = ida_simple_get(&nd_region->btt_ida, 0, 0, GFP_KERNEL);
-       if (nd_btt->id < 0) {
-               kfree(nd_btt);
-               return NULL;
-       }
+       if (nd_btt->id < 0)
+               goto out_nd_btt;
 
        nd_btt->lbasize = lbasize;
-       if (uuid)
+       if (uuid) {
                uuid = kmemdup(uuid, 16, GFP_KERNEL);
+               if (!uuid)
+                       goto out_put_id;
+       }
        nd_btt->uuid = uuid;
        dev = &nd_btt->dev;
        dev_set_name(dev, "btt%d.%d", nd_region->id, nd_btt->id);
@@ -220,6 +221,13 @@ static struct device *__nd_btt_create(struct nd_region 
*nd_region,
                return NULL;
        }
        return dev;
+
+out_put_id:
+       ida_simple_remove(&nd_region->btt_ida, nd_btt->id);
+
+out_nd_btt:
+       kfree(nd_btt);
+       return NULL;
 }
 
 struct device *nd_btt_create(struct nd_region *nd_region)
-- 
2.17.1