On Fri, 2020-10-09 at 10:16 +0200, Greg KH wrote: > On Fri, Oct 09, 2020 at 10:06:14AM +0200, Johannes Berg wrote: > > We used to say the proxy_fops weren't needed and it wasn't an issue, and > > then still implemented it. Dunno. I'm not really too concerned about it > > myself, only root can hold the files open and remove modules ... > > proxy_fops were needed because devices can be removed from the system at > any time, causing their debugfs files to want to also be removed. It > wasn't because of unloading kernel code. Indeed, that's true. Still, we lived with it for years. Anyway, like I said, I really just did this more to see that it _could_ be done, not to suggest that it _should_ :-) I think adding the .owner everywhere would be good, and perhaps we can somehow put a check somewhere like WARN_ON(is_module_address((unsigned long)fops) && !fops->owner); to prevent the issue in the future? johannes
