X-Git-Url: http://demsky.eecs.uci.edu/git/?a=blobdiff_plain;f=kernel%2Ffreezer.c;h=8b2afc1c9df0c698eccd86664d25c33ed647fea7;hb=3aa78e0cb5c9b8b4ed2a617bb1e1542bfb508379;hp=c38893b0efbaa39d770b11546dba9e97ec53ff51;hpb=5c69bed266adadf9fd334e68a7ac586b625e9547;p=firefly-linux-kernel-4.4.55.git

diff --git a/kernel/freezer.c b/kernel/freezer.c
index c38893b0efba..8b2afc1c9df0 100644
--- a/kernel/freezer.c
+++ b/kernel/freezer.c
@@ -110,6 +110,18 @@ bool freeze_task(struct task_struct *p)
 {
 	unsigned long flags;
 
+	/*
+	 * This check can race with freezer_do_not_count, but worst case that
+	 * will result in an extra wakeup being sent to the task.  It does not
+	 * race with freezer_count(), the barriers in freezer_count() and
+	 * freezer_should_skip() ensure that either freezer_count() sees
+	 * freezing == true in try_to_freeze() and freezes, or
+	 * freezer_should_skip() sees !PF_FREEZE_SKIP and freezes the task
+	 * normally.
+	 */
+	if (freezer_should_skip(p))
+		return false;
+
 	spin_lock_irqsave(&freezer_lock, flags);
 	if (!freezing(p) || frozen(p)) {
 		spin_unlock_irqrestore(&freezer_lock, flags);