Re: [PATH v2] scsi: scsi_dh_rdac: Avoid crash during rdac_bus_attach

[yebin <yebin10@huawei.com>]

On 2021/7/23 12:04, Bart Van Assche wrote:
> On 1/12/21 10:31 PM, Ye Bin wrote:
>>   	sdev->handler_data = NULL;
>> +	synchronize_rcu();
>>   	kfree(h);
> What is the purpose of the new synchronize_rcu() call?
Thanks for your reply.
Yes, I add new synchronize_rcu() call is to wait until *h is no longer 
in use. If free
"h" right now , mybe lead to UAF.
> If its purpose is
> to wait until *h is no longer in use, please use kfree_rcu() instead.
struct rdac_dh_data {
         struct list_head        node;
         .....
}
As rdac_dh_data.node type is "struct list_head", but  kfree_rcu the 
first parameter type is
"struct rcu_head". So we can only use synchronize_rcu() at here.
>
> Thanks,
>
> Bart.
> .
>