Merge commit 'afabf37012e839802f9f3819f621e16aa4acefd2' into upstreaming

update from cm-13.0

Conflicts:
	Makefile
	crypto/algapi.c
	drivers/char/diag/diagchar.h
	drivers/char/diag/diagchar_core.c
	drivers/misc/Makefile
	kernel/timeconst.pl

1 files changed, 9 insertions, 0 deletions

diff --git a/kernel/cgroup.c b/kernel/cgroup.c
index 2ba3bac..e4f8595 100644
--- a/kernel/cgroup.c
+++ b/kernel/cgroup.c
@@ -366,10 +366,19 @@ static void free_css_set_work(struct work_struct *work)
 		struct cgroup *cgrp = link->cgrp;
 		list_del(&link->cg_link_list);
 		list_del(&link->cgrp_link_list);
+
+                /*
+                 * We may not be holding cgroup_mutex, and if cgrp->count is
+                 * dropped to 0 the cgroup can be destroyed at any time, hence
+                 * rcu_read_lock is used to keep it alive.
+                 */
+                rcu_read_lock();
 		if (atomic_dec_and_test(&cgrp->count)) {
 			check_for_release(cgrp);
 			cgroup_wakeup_rmdir_waiter(cgrp);
 		}
+                rcu_read_unlock();
+
 		kfree(link);
 	}
 	write_unlock(&css_set_lock);