[PATCH 7/8] cachefiles: Fix NULL pointer dereference in object->file

[Zizhi Wo]

在 2024/10/10 19:26, David Howells 写道:
> Zizhi Wo <wozizhi at huawei.com> wrote:
> 
>> +	spin_lock(&object->lock);
>>   	if (object->file) {
>>   		fput(object->file);
>>   		object->file = NULL;
>>   	}
>> +	spin_unlock(&object->lock);
> 
> I would suggest stashing the file pointer in a local var and then doing the
> fput() outside of the locks.
> 
> David
> 
> 

If fput() is executed outside the lock, I am currently unsure how to
guarantee that file in __cachefiles_write() does not trigger null
pointer dereference...

Thanks,
Zizhi Wo