[SRU][T,U,V] fix per-cpu workqueue crash

[Kamal Mostafa]

From: Kamal Mostafa <kamal at canonical.com>

BugLink: http://bugs.launchpad.net/bugs/1546320

This crash manifests in [ T, U, V ] but not >= W due to another change.

The primary fix is to revert of "workqueue: make sure delayed work run
in local cpu" (recently reverted in mainline, clean cherry-pick, and
positive test results in the LP bug).

The secondary fix, as referenced in the revert, is mainline commit
"vmstat: explicitly schedule..." (which needs an individual backport for
each of T, U, and V).

Both patches are pending for their respective stable kernels.

 -Kamal

-------------

Linus Torvalds (1):
  vmstat: explicitly schedule per-cpu work on the CPU we need it to run
    on

Tejun Heo (1):
  Revert "workqueue: make sure delayed work run in local cpu"

 kernel/workqueue.c | 8 ++++----
 mm/vmstat.c        | 3 ++-
 2 files changed, 6 insertions(+), 5 deletions(-)

-- 
2.7.0