i2c: fix memleak in i2c_new_client_device()

Yang Yingliang reported a memleak:
===

I got memory leak as follows when doing fault injection test:

unreferenced object 0xffff888014aec078 (size 8):
  comm "xrun", pid 356, jiffies 4294910619 (age 16.332s)
  hex dump (first 8 bytes):
    31 2d 30 30 31 63 00 00                          1-001c..
  backtrace:
    [<00000000eb56c0a9>] __kmalloc_track_caller+0x1a6/0x300
    [<000000000b220ea3>] kvasprintf+0xad/0x140
    [<00000000b83203e5>] kvasprintf_const+0x62/0x190
    [<000000002a5eab37>] kobject_set_name_vargs+0x56/0x140
    [<00000000300ac279>] dev_set_name+0xb0/0xe0
    [<00000000b66ebd6f>] i2c_new_client_device+0x7e4/0x9a0

If device_register() returns error in i2c_new_client_device(),
the name allocated by i2c_dev_set_name() need be freed. As
comment of device_register() says, it should use put_device()
to give up the reference in the error path.

===
I think this solution is less intrusive and more robust than he
originally proposed solutions, though.

Reported-by: Yang Yingliang <yangyingliang@huawei.com>
Closes: http://patchwork.ozlabs.org/project/linux-i2c/patch/20221124085448.3620240-1-yangyingliang@huawei.com/
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index 60746652fd5255cb998c5690f985430aaf0d773c..7f30bcceebaed3380ce0b3325e5e48ca0dba8807 100644 (file)
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -931,8 +931,9 @@ int i2c_dev_irq_from_resources(const struct resource *resources,
 struct i2c_client *
 i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *info)
 {
-       struct i2c_client       *client;
-       int                     status;
+       struct i2c_client *client;
+       bool need_put = false;
+       int status;
 
        client = kzalloc(sizeof *client, GFP_KERNEL);
        if (!client)
@@ -970,7 +971,6 @@ i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *inf
        client->dev.fwnode = info->fwnode;
 
        device_enable_async_suspend(&client->dev);
-       i2c_dev_set_name(adap, client, info);
 
        if (info->swnode) {
                status = device_add_software_node(&client->dev, info->swnode);
@@ -982,6 +982,7 @@ i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *inf
                }
        }
 
+       i2c_dev_set_name(adap, client, info);
        status = device_register(&client->dev);
        if (status)
                goto out_remove_swnode;
@@ -993,6 +994,7 @@ i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *inf
 
 out_remove_swnode:
        device_remove_software_node(&client->dev);
+       need_put = true;
 out_err_put_of_node:
        of_node_put(info->of_node);
 out_err:
@@ -1000,7 +1002,10 @@ out_err:
                "Failed to register i2c client %s at 0x%02x (%d)\n",
                client->name, client->addr, status);
 out_err_silent:
-       kfree(client);
+       if (need_put)
+               put_device(&client->dev);
+       else
+               kfree(client);
        return ERR_PTR(status);
 }
 EXPORT_SYMBOL_GPL(i2c_new_client_device);