Re: [patch v3] mm, oom: fix unnecessary killing of additional processes

[Tetsuo Handa]

On 2018/07/20 17:41, David Rientjes wrote:
> Absent oom_lock serialization, this is exactly working as intended.  You 
> could argue that once the thread has reached exit_mmap() and begins oom 
> reaping that it should be allowed to finish before the oom reaper declares 
> MMF_OOM_SKIP.  That could certainly be helpful, I simply haven't 
> encountered a usecase where it were needed.  Or, we could restart the oom 
> expiration when MMF_UNSTABLE is set and deem that progress is being made 
> so it give it some extra time.  In practice, again, we haven't seen this 
> needed.  But either of those are very easy to add in as well.  Which would 
> you prefer?

I don't think we need to introduce user-visible knob interface (even if it is in
debugfs), for I think that my approach can solve your problem. Please try OOM lockup
(CVE-2016-10723) mitigation patch ( https://marc.info/?l=linux-mm&m=153112243424285&w=4 )
and my cleanup patch ( [PATCH 1/2] at https://marc.info/?l=linux-mm&m=153119509215026&w=4 )
on top of linux.git . And please reply how was the result, for I'm currently asking
Roman whether we can apply these patches before applying the cgroup-aware OOM killer.