On Wed 19-10-16 18:44:29, Oleg Nesterov wrote: > On 10/19, Michal Hocko wrote: > > > > On Wed 19-10-16 18:12:08, Oleg Nesterov wrote: > > > On 10/19, Michal Hocko wrote: > > > > > > > > Why would we even want to open that file if there is no mm struct? > > > > > > Agreed this is strange, but I am not sure we can change this old > > > behaviour. Say, cat /proc/$pid-of-kthread/mem doesn't fail, it shows > > > the "empty mm". > > > > What kind of application would break? > > I have no idea, probably nobody will ever notice this change, just > I am always nervous when it comes to user-visible changes. > > But why do we want this change? Not that I am going to argue if you > submit a patch, but personally I see no real point.
I find it much easier to not allow open than a) have a weird side effects like seeing a hijacked mm and b) risk that similar NULL ptr will repeat again because all the code paths have to check for it explicitly. -- Michal Hocko SUSE Labs
