[3.13.y.z extended stable] Patch "workqueue: fix bugs in wq_update_unbound_numa() failure path" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    workqueue: fix bugs in wq_update_unbound_numa() failure path

to the linux-3.13.y-queue branch of the 3.13.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11.4.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 47f445e12853a6f022345b4e59b7eec1043fe84a Mon Sep 17 00:00:00 2001
From: Daeseok Youn <daeseok.youn at gmail.com>
Date: Wed, 16 Apr 2014 14:32:29 +0900
Subject: workqueue: fix bugs in wq_update_unbound_numa() failure path

commit 77f300b198f93328c26191b52655ce1b62e202cf upstream.

wq_update_unbound_numa() failure path has the following two bugs.

- alloc_unbound_pwq() is called without holding wq->mutex; however, if
  the allocation fails, it jumps to out_unlock which tries to unlock
  wq->mutex.

- The function should switch to dfl_pwq on failure but didn't do so
  after alloc_unbound_pwq() failure.

Fix it by regrabbing wq->mutex and jumping to use_dfl_pwq on
alloc_unbound_pwq() failure.

Signed-off-by: Daeseok Youn <daeseok.youn at gmail.com>
Acked-by: Lai Jiangshan <laijs at cn.fujitsu.com>
Signed-off-by: Tejun Heo <tj at kernel.org>
Fixes: 4c16bd327c74 ("workqueue: implement NUMA affinity for unbound workqueues")
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 kernel/workqueue.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index a8381cf..6b1b746 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -4093,7 +4093,8 @@ static void wq_update_unbound_numa(struct workqueue_struct *wq, int cpu,
 	if (!pwq) {
 		pr_warning("workqueue: allocation failed while updating NUMA affinity of \"%s\"\n",
 			   wq->name);
-		goto out_unlock;
+		mutex_lock(&wq->mutex);
+		goto use_dfl_pwq;
 	}

 	/*
--
1.9.1