Hi Andy,
On 1/30/21 1:26 AM, Andy Shevchenko wrote:
On Fri, Jan 29, 2021 at 2:01 PM <quanyang.wang@xxxxxxxxxxxxx> wrote:
From: Quanyang Wang <quanyang.wang@xxxxxxxxxxxxx>
In gpiochip_add_data_with_key, we should check the return value of
dev_set_name to ensure that device name is allocated successfully
and then add a label on the error path to free device name to fix
kmemleak as below:
Thanks for the report.
Unfortunately...
+ ret = dev_set_name(&gdev->dev, GPIOCHIP_NAME "%d", gdev->id);
+ if (ret)
+ goto err_free_ida;
...
+err_free_dev_name:
+ kfree(dev_name(&gdev->dev));
...this approach seems to create a possible double free if I'm not mistaken.
Thanks for your comment. I didn't catch the double free. Would you
please point it out?
The idea is that device name should be cleaned in kobject ->release()
callback when device is put.
Yes, the device name should be freed by calling put_device(&gdev->dev).
But int gpiochip_add_data_with_key,
when running dev_set_name, "gdev->dev.release" hasn't been installed
until in the tail of gpiochip_add_data_with_key.
So we couldn't call put_device here.
Any suggestion is much appreciated.
Thanks,
Quanyang
Can you elaborate?
