On Fri, May 24, 2019 at 09:33:13AM +0100, Jon Hunter wrote:
On 24/05/2019 01:50, Gen Zhang wrote:
In tegra_wm9712_driver_probe(), 'machine->codec' is allocated by platform_device_alloc(). When it is NULL, function returns ENOMEM. However, 'machine' is allocated by devm_kzalloc() before this site. Thus we should free 'machine' before function ends to prevent memory leaking.
Memory allocated by devm_xxx() is automatically freed on failure so this is not correct.
Thanks for your comments, Jon. But after I examined the code, I am still confused about the usage of devm_kmalloc(). You can kindly refer to hisi_sas_debugfs_init() in drivers/scsi/hisi_sas/hisi_sas_main.c. And devm_kfree() is used to free a memory allocated by devm_kmalloc(). And I found other situations similar to this in other files.
So, I hope you can give me some guidance on this. Thanks!
Further, we should free 'machine->util_data', 'machine->codec' and 'machine' before this function normally ends to prevent memory leaking.
This is also incorrect. Why would we free all resources after successfully initialising the driver?
I re-checked this part, and it is totally incorrect. It should be deleted.
Thanks Gen