1 files changed, 41 insertions, 9 deletions

diff --git a/kernel/power/process.c b/kernel/power/process.c
index 899e07479..3bd3a1185 100644
--- a/kernel/power/process.c
+++ b/kernel/power/process.c
@@ -118,6 +118,30 @@ static int try_to_freeze_tasks(bool user_only)
 	return todo ? -EBUSY : 0;
 }
 
+static bool __check_frozen_processes(void)
+{
+	struct task_struct *g, *p;
+
+	for_each_process_thread(g, p)
+		if (p != current && !freezer_should_skip(p) && !frozen(p))
+			return false;
+
+	return true;
+}
+
+/*
+ * Returns true if all freezable tasks (except for current) are frozen already
+ */
+static bool check_frozen_processes(void)
+{
+	bool ret;
+
+	read_lock(&tasklist_lock);
+	ret = __check_frozen_processes();
+	read_unlock(&tasklist_lock);
+	return ret;
+}
+
 /**
  * freeze_processes - Signal user space processes to enter the refrigerator.
  * The current thread will not be frozen.  The same process that calls
@@ -128,6 +152,7 @@ static int try_to_freeze_tasks(bool user_only)
 int freeze_processes(void)
 {
 	int error;
+	int oom_kills_saved;
 
 	error = __usermodehelper_disable(UMH_FREEZING);
 	if (error)
@@ -142,22 +167,29 @@ int freeze_processes(void)
 	pm_wakeup_clear();
 	pr_info("Freezing user space processes ... ");
 	pm_freezing = true;
+	oom_kills_saved = oom_kills_count();
 	error = try_to_freeze_tasks(true);
 	if (!error) {
 		__usermodehelper_set_disable_depth(UMH_DISABLED);
-		pr_cont("done.");
+		oom_killer_disable();
+
+		/*
+		 * There might have been an OOM kill while we were
+		 * freezing tasks and the killed task might be still
+		 * on the way out so we have to double check for race.
+		 */
+		if (oom_kills_count() != oom_kills_saved &&
+		    !check_frozen_processes()) {
+			__usermodehelper_set_disable_depth(UMH_ENABLED);
+			pr_cont("OOM in progress.");
+			error = -EBUSY;
+		} else {
+			pr_cont("done.");
+		}
 	}
 	pr_cont("\n");
 	BUG_ON(in_atomic());
 
-	/*
-	 * Now that the whole userspace is frozen we need to disbale
-	 * the OOM killer to disallow any further interference with
-	 * killable tasks.
-	 */
-	if (!error && !oom_killer_disable())
-		error = -EBUSY;
-
 	if (error)
 		thaw_processes();
 	return error;