Messages in this thread | | | Date | Tue, 10 Mar 2020 12:17:10 +0100 | From | Michal Hocko <> | Subject | Re: [PATCHv2] memcg: fix NULL pointer dereference in __mem_cgroup_usage_unregister_event |
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On Tue 10-03-20 13:41:49, Kirill A. Shutemov wrote: > On Tue, Mar 10, 2020 at 10:48:36AM +0100, Michal Hocko wrote: > > [Cc Kirill, I didn't realize he has implemented this code] > > My first non-trivial mm contribution :P
Everybody has to pay for sins of youth :p
[...]
> > It seems that the code has been broken since 2c488db27b61 ("memcg: clean > > up memory thresholds"). We've had 371528caec55 ("mm: memcg: Correct > > unregistring of events attached to the same eventfd") but it didn't > > catch this case for some reason. Unless I am missing something the code > > was broken back then already. Kirill please double check after me. > > I think the issue exitsted before 2c488db27b61. The fields had different > names back then. > > The logic to make unregister never-fail is added in 907860ed381a > ("cgroups: make cftype.unregister_event() void-returning"). I believe the > Fixes should point there.
Yes, you seem to be right. It doesn't make a difference much as both went in to the same kernel but a proper Fixes tag is really valuable.
Thanks for looking into that.
-- Michal Hocko SUSE Labs
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