On Fri, 2020-10-09 at 08:34 +0000, David Laight wrote: > > > 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? > > Does it ever make any sense to set .owner to anything other than > THIS_MODULE? No. But I believe THIS_MODULE is NULL for built-in code, so we can't just WARN_ON(!fops->owner). > If not the code that saves the 'struct file_operations' address > ought to be able to save the associated module. No, it's const. > I was also wondering if this affects normal opens? > They should hold a reference on the module to stop it being unloaded. > Does that rely on .owner being set? Yes. > For debugfs surely it is possible to determine and save THIS_MODULE > when he nodes are registers and do a try_module_get() in the open? I don't really see where to save it? johannes
