From: Tejun Heo <tj@kernel.org>
Date: Mon, 8 Sep 2014 23:02:45 +0000 (+0900)
Subject: percpu: fix locking regression in the failure path of pcpu_alloc()
X-Git-Tag: fixes-against-v3.18-rc2~134^2~16
X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=23cb8981ed929b4dd48141401cd0fd31e0fa4ed0;p=pandora-kernel.git

percpu: fix locking regression in the failure path of pcpu_alloc()

While updating locking, b38d08f3181c ("percpu: restructure locking")
broke pcpu_create_chunk() creation path in pcpu_alloc().  It returns
without releasing pcpu_alloc_mutex.  Fix it.

Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Julia Lawall <julia.lawall@lip6.fr>
---

diff --git a/mm/percpu.c b/mm/percpu.c
index 867efd38d879..af3dd2704efd 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -974,6 +974,7 @@ restart:
 	if (list_empty(&pcpu_slot[pcpu_nr_slots - 1])) {
 		chunk = pcpu_create_chunk();
 		if (!chunk) {
+			mutex_unlock(&pcpu_alloc_mutex);
 			err = "failed to allocate new chunk";
 			goto fail;
 		}