Protect __release_resource against resources without parents

raspberrypi inclusion
category: feature
bugzilla: 50432

--------------------------------

Without this patch, removing a device tree overlay can crash here.
Signed-off-by: NPhil Elwell <phil@raspberrypi.org>
Signed-off-by: NFang Yafen <yafen@iscas.ac.cn>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

kernel/resource.c

@@ -214,6 +214,12 @@ static int __release_resource(struct resource *old, bool release_child)
 {
 	struct resource *tmp, **p, *chd;
 
+	if (!old->parent) {
+		WARN(old->sibling, "sibling but no parent");
+		if (old->sibling)
+			return -EINVAL;
+		return 0;
+	}
 	p = &old->parent->child;
 	for (;;) {
 		tmp = *p;