From: Phil Elwell <phil@raspberrypi.org>
Date: Fri, 13 Mar 2015 12:43:36 +0000 (+0000)
Subject: Protect __release_resource against resources without parents
X-Git-Tag: archive/raspbian/4.9.13-1+rpi1~8^2~196
X-Git-Url: https://dgit.raspbian.org/%22http://www.example.com/cgi/%22/%22http:/www.example.com/cgi/%22?a=commitdiff_plain;h=d3078bd3040aa01758d08993ddc73fc374c5a828;p=linux-4.9.git

Protect __release_resource against resources without parents

Without this patch, removing a device tree overlay can crash here.

Signed-off-by: Phil Elwell <phil@raspberrypi.org>
---

diff --git a/kernel/resource.c b/kernel/resource.c
index 9b5f04404152..f8a9af6e6b91 100644
--- a/kernel/resource.c
+++ b/kernel/resource.c
@@ -246,6 +246,12 @@ 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;