On Fri, 9 Oct 2020 at 01:14, Johannes Berg <johannes@xxxxxxxxxxxxxxxx> wrote: On Thu, 2020-10-08 at 15:59 +0000, David Laight wrote: Hi Johannes and David, Thank you for the review! > From: Taehee Yoo > > Sent: 08 October 2020 16:49 > > > > When debugfs file is opened, its module should not be removed until > > it's closed. > > Because debugfs internally uses the module's data. > > So, it could access freed memory. > > > > In order to avoid panic, it just sets .owner to THIS_MODULE. > > So that all modules will be held when its debugfs file is opened. > > Can't you fix it in common code? > Yeah I was just wondering that too - weren't the proxy_fops even already > intended to fix this? I didn't try to fix this issue in the common code(debugfs). Because I thought It's a typical pattern of panic and THIS_MODULE can fix it clearly. So I couldn't think there is a root reason in the common code. > The modules _should_ be removing the debugfs files, and then the > proxy_fops should kick in, no? If I understand your mention correctly, you mean that when the module is being removed, the opened file should be closed automatically by debugfs filesystem. Is that right? > So where's the issue? > johannes Thanks a lot! Taehee
