[PATCH net] net: atm: fix memory leak in atm_register_sysfs when device_register fail

[Wang Liang <wangliang74@huawei.com>]

When device_register() return error in atm_register_sysfs(), which can be
triggered by kzalloc fail in device_private_init() or other reasons,
kmemleak reports the following memory leaks:

unreferenced object 0xffff88810182fb80 (size 8):
  comm "insmod", pid 504, jiffies 4294852464
  hex dump (first 8 bytes):
    61 64 75 6d 6d 79 30 00                          adummy0.
  backtrace (crc 14dfadaf):
    __kmalloc_node_track_caller_noprof+0x335/0x450
    kvasprintf+0xb3/0x130
    kobject_set_name_vargs+0x45/0x120
    dev_set_name+0xa9/0xe0
    atm_register_sysfs+0xf3/0x220
    atm_dev_register+0x40b/0x780
    0xffffffffa000b089
    do_one_initcall+0x89/0x300
    do_init_module+0x27b/0x7d0
    load_module+0x54cd/0x5ff0
    init_module_from_file+0xe4/0x150
    idempotent_init_module+0x32c/0x610
    __x64_sys_finit_module+0xbd/0x120
    do_syscall_64+0xa8/0x270
    entry_SYSCALL_64_after_hwframe+0x77/0x7f

When device_create_file() return error in atm_register_sysfs(), the same
issue also can be triggered.

Function put_device() should be called to release kobj->name memory and
other device resource, instead of kfree().

Fixes: 1fa5ae857bb1 ("driver core: get rid of struct device's bus_id string array")
Signed-off-by: Wang Liang <wangliang74@huawei.com>
---
 net/atm/resources.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/atm/resources.c b/net/atm/resources.c
index b19d851e1f44..7c6fdedbcf4e 100644
--- a/net/atm/resources.c
+++ b/net/atm/resources.c
@@ -112,7 +112,9 @@ struct atm_dev *atm_dev_register(const char *type, struct device *parent,
 
 	if (atm_proc_dev_register(dev) < 0) {
 		pr_err("atm_proc_dev_register failed for dev %s\n", type);
-		goto out_fail;
+		mutex_unlock(&atm_dev_mutex);
+		kfree(dev);
+		return NULL;
 	}
 
 	if (atm_register_sysfs(dev, parent) < 0) {
@@ -128,7 +130,7 @@ struct atm_dev *atm_dev_register(const char *type, struct device *parent,
 	return dev;
 
 out_fail:
-	kfree(dev);
+	put_device(&dev->class_dev);
 	dev = NULL;
 	goto out;
 }
-- 
2.34.1