Input: iqs7222 - avoid dereferencing a NULL pointer

Select callers of iqs7222_parse_props() do not expect a child node
to be derived and returned via pointer. As such, these callers set
**child_node to NULL. However, this pointer is dereferenced in all
cases.

To solve this problem, dereference the pointer only for cases that
expect a child node in the first place. In these cases, the caller
provides a valid pointer.

Fixes: e505edaedcb9 ("Input: add support for Azoteq IQS7222A/B/C")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Jeff LaBundy <jeff@labundy.com>
Link: https://lore.kernel.org/r/20220417214132.497487-1-jeff@labundy.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

diff --git a/drivers/input/misc/iqs7222.c b/drivers/input/misc/iqs7222.c
index c0b2732..6b41387 100644 (file)
--- a/drivers/input/misc/iqs7222.c
+++ b/drivers/input/misc/iqs7222.c
@@ -1534,8 +1534,8 @@ static int iqs7222_parse_props(struct iqs7222_private *iqs7222,
                               enum iqs7222_reg_key_id reg_key)
 {
        u16 *setup = iqs7222_setup(iqs7222, reg_grp, child_index);
-       struct fwnode_handle *reg_grp_node = *child_node;
        struct i2c_client *client = iqs7222->client;
+       struct fwnode_handle *reg_grp_node;
        char reg_grp_name[16];
        int i;
 
@@ -1550,7 +1550,8 @@ static int iqs7222_parse_props(struct iqs7222_private *iqs7222,
                 * for additional group-specific processing. In some cases, the
                 * child node may have already been derived.
                 */
-               if (*child_node)
+               reg_grp_node = *child_node;
+               if (reg_grp_node)
                        break;
 
                snprintf(reg_grp_name, sizeof(reg_grp_name), "%s-%d",