ACK: [SRU][Bionic][PATCH 0/1] Fixes for LP1800849 [v2]
Colin Ian King
colin.king at canonical.com
Fri Nov 2 19:16:52 UTC 2018
On 02/11/2018 19:11, 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.
This is a clean upstream cherry pick that addresses this known issue. I
see it will land via stable, but lets pick this up sooner if possible.
Acked-by: Colin Ian King <colin.king at canonical.com>
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