[PATCH] watchdog: Fix double-free in watchdog_cdev_register

[Dinghao Liu]

When misc_register() fails, wd_data will be released by the
release callback function watchdog_core_data_release(), so
we don't need to free it again. But when watchdog_kworker is
NULL, we should free wd_data to prevent memleak.

Fixes: cb36e29bb0e4b ("watchdog: initialize device before misc_register")
Signed-off-by: Dinghao Liu <dinghao....@zju.edu.cn>
---
 drivers/watchdog/watchdog_dev.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c
index 6798addabd5a..8ee78e26feb1 100644
--- a/drivers/watchdog/watchdog_dev.c
+++ b/drivers/watchdog/watchdog_dev.c
@@ -994,8 +994,10 @@ static int watchdog_cdev_register(struct watchdog_device 
*wdd)
        wd_data->wdd = wdd;
        wdd->wd_data = wd_data;
 
-       if (IS_ERR_OR_NULL(watchdog_kworker))
+       if (IS_ERR_OR_NULL(watchdog_kworker)) {
+               kfree(wd_data);
                return -ENODEV;
+       }
 
        device_initialize(&wd_data->dev);
        wd_data->dev.devt = MKDEV(MAJOR(watchdog_devt), wdd->id);
@@ -1021,7 +1023,6 @@ static int watchdog_cdev_register(struct watchdog_device 
*wdd)
                                pr_err("%s: a legacy watchdog module is 
probably present.\n",
                                        wdd->info->identity);
                        old_wd_data = NULL;
-                       kfree(wd_data);
                        return err;
                }
        }
-- 
2.17.1