[SRU][Xenial][PATCH 0/2] Fixes for LP #1687512

[Daniel Axtens]

BugLink: https://bugs.launchpad.net/bugs/1687512

[Impact]
Apache Mesos and Kubernetes workloads on Xenial cause a panic
(NULL pointer dereference) in the completely fair scheduler.

These panics are in pick_next_entity and include pick_next_task_fair
in the call stack.

[Fix]
Cherry-picking both
754bd598be9bbc953bc709a9e8ed7f3188bfb9d7
(http://lkml.kernel.org/r/146608183552.21905.15924473394414832071.stgit@buzz)
and
094f469172e00d6ab0a3130b0e01c83b3cf3a98d
(http://lkml.kernel.org/r/146608182119.21870.8439834428248129633.stgit@buzz)
fix the crash.
They appear to be intended as a series - they were posted to LKML at
the same time.

[Testcase]
The fix has been validated by the user who reported the bug

[Notes]
These commits went upstream in 4.7-rc5, so they are already in
Yakkety/Zesty/Artful.

Konstantin Khlebnikov (2):
  sched/fair: Do not announce throttled next buddy in
    dequeue_task_fair()
  sched/fair: Initialize throttle_count for new task-groups lazily

 kernel/sched/fair.c  | 29 ++++++++++++++++++++++++-----
 kernel/sched/sched.h |  2 +-
 2 files changed, 25 insertions(+), 6 deletions(-)

-- 
2.11.0