On Fri, 9 Oct 2020 at 14:39, Nicolai Stange <nstange@xxxxxxx> wrote: > Hi Nicolai, Thank you for the review! > Taehee Yoo <ap420073@xxxxxxxxx> writes: > > > 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: > > > >> 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. > > Yes, the file_operations' ->release() to be more specific -- that's not > covered by debugfs' proxy fops. > > > >> > 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. > > That's correct, ->owner should get set properly, c.f. my other mail in > this thread. > Thanks a lot for verifying it! Taehee
