APPLIED/cmnt: [SRU][Bionic][PATCH 0/1] Fixes for LP1800849 [v2]

[Khaled Elmously]

Unable to extract the patches from the email - I cherry-picked the patches from mainline and manually edited the commit message.

On 2018-11-02 20:11:12 , Frank Heimes wrote:
> BugLink: http://bugs.launchpad.net/bugs/1800849
> 
> == SRU Justification ==
> 
> Description: kvm: fix deadlock when killed by oom
> Symptom: oom killer leaves processes in a deadlock state.
> Problem: The problem arises in the rare cases in which
>          handle_mm_fault does not release the mm_sem.
> Solution: Correct the issue by manually release the mm_sem when needed.
> 
> == Fix ==
> 
> 306d6c49ac9ded11114cb53b0925da52f2c2ada1 ("s390/kvm: fix deadlock when
> killed by oom")
> 
> == Regression Potential ==
> 
> Low and minimal, because:
> - s390x only
> - limited to one single file: /arch/s390/mm/fault.c
> - just two additional lines added (if stmt)
> - Xenial and Cosmic already have this commit via upstream stable updates.
> - Hence patch is just missing in Bionic.
> - Test kernel was build for testting.
> 
> == Test Case ==
> 
> Create numerous KVM guests so that the host starts swapping
> and memory becomes overcomitted and the oom killer is triggered.

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