On Tue, Apr 25, 2006 at 08:53:16PM +0400, Artem B. Bityutskiy wrote:Right. I just thought you expose sysfs files even if you're not mounted. Sorry, I did not dig deeply.
Hello,
last time I tried to use "bare" sysfs functions to create my sysfs hierarchy I ended up with a problem that the module refcount is not increased when those sysfs files are opened. So I could open a sysfs file from userspace, do rmmod and enjoy oops.
Then I started using the class and class_device stuff, which have an .owner field, and all became fine.
I'm not sure if this is a problem of sysfs, but I suspect it could take care of module refcount better.
In your patch, I looked for THIS_MODULE pattern and did not find. I did not try, but I suspect your code is not devoid of the problem I described. So, this is just FYI and may be not the case.
Others have also alluded to /sys/fs/ races that we'll probably need to
resolve. In this case the question is more about umount than rmmod since
the mount should reference the module.