linux-kernel - [PATCH v2] i2c: core: Fix possible memleak in i2c_new_client

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Message-ID: <20220511012738.3031346-1-yangyingliang@huawei.com>
Date:   Wed, 11 May 2022 09:27:38 +0800
From:   Yang Yingliang <yangyingliang@...wei.com>
To:     <linux-kernel@...r.kernel.org>, <linux-i2c@...r.kernel.org>
CC:     <wsa@...nel.org>
Subject: [PATCH v2] i2c: core: Fix possible memleak in i2c_new_client_device()

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

In error path after calling dev_set_name() which called by
i2c_dev_set_name(), the put_device() should be used to give up
the device reference, then the name allocated in dev_set_name()
will be freed in kobject_cleanup().
In this patch, I splited device_register() into device_initialize()
and device_add() to make the code more clear.

Reported-by: Hulk Robot <hulkci@...wei.com>
Signed-off-by: Yang Yingliang <yangyingliang@...wei.com>
---
v2:
  split device_register() into device_initialize() and device_add()
---
 drivers/i2c/i2c-core-base.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/i2c/i2c-core-base.c b/drivers/i2c/i2c-core-base.c
index d43db2c3876e..e7dded8b037b 100644
--- a/drivers/i2c/i2c-core-base.c
+++ b/drivers/i2c/i2c-core-base.c
@@ -928,6 +928,11 @@ i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *inf
 	client->flags = info->flags;
 	client->addr = info->addr;
 
+	client->dev.parent = &client->adapter->dev;
+	client->dev.bus = &i2c_bus_type;
+	client->dev.type = &i2c_client_type;
+	device_initialize(&client->dev);
+
 	client->init_irq = info->irq;
 	if (!client->init_irq)
 		client->init_irq = i2c_dev_irq_from_resources(info->resources,
@@ -947,9 +952,6 @@ i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *inf
 	if (status)
 		goto out_err;
 
-	client->dev.parent = &client->adapter->dev;
-	client->dev.bus = &i2c_bus_type;
-	client->dev.type = &i2c_client_type;
 	client->dev.of_node = of_node_get(info->of_node);
 	client->dev.fwnode = info->fwnode;
 
@@ -966,7 +968,7 @@ i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *inf
 		}
 	}
 
-	status = device_register(&client->dev);
+	status = device_add(&client->dev);
 	if (status)
 		goto out_remove_swnode;
 
@@ -984,7 +986,7 @@ i2c_new_client_device(struct i2c_adapter *adap, struct i2c_board_info const *inf
 		"Failed to register i2c client %s at 0x%02x (%d)\n",
 		client->name, client->addr, status);
 out_err_silent:
-	kfree(client);
+	put_device(&client->dev);
 	return ERR_PTR(status);
 }
 EXPORT_SYMBOL_GPL(i2c_new_client_device);
-- 
2.25.1