On Tue, Dec 12, 2017 at 08:03:43AM -0500, Theodore Ts'o wrote: > On Tue, Dec 12, 2017 at 02:20:32PM +0900, Byungchul Park wrote: > > The *problem* is false positives, since locks and waiters in > > kernel are not classified properly, at the moment, which is just > > a fact that is not related to cross-release stuff at all. IOW, > > that would be useful once all locks and waiters are classified > > correctly. It might take time but the classifying is a must-do > > we have to keep doing. > > This is the wrong attitude. The reason why LOCKDEP was so powerful > was because it automatically classified locks, instead of requiring > developers to document the locking hierarchy. Requiring developers to > have to document and classified locks --- especially when the d*mned > mechanisms for doign so are so primitive and not even documented --- > is a complete non-strarter. That's not fair. We had to annotate i_mutex nesting, for example, and several other places. crosslock doesn't change anything in this respect, it's just that the case that you hit every damn day as a filesystem developer is something that the normal person almost never does. > So are you willing to take my patch? Or give me permission to keep in > the ext4 tree? He sent a patch earlier ...