runtime: validate lfnode addresses

Change-Id: Ic8c506289caaf6218494e5150d10002e0232feaa
Reviewed-on: https://go-review.googlesource.com/85876
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rick Hudson <rlh@golang.org>

1 files changed, 10 insertions, 0 deletions

diff --git a/src/runtime/lfstack.go b/src/runtime/lfstack.go
index 4787c5be3f..406561a275 100644
--- a/src/runtime/lfstack.go
+++ b/src/runtime/lfstack.go
@@ -55,3 +55,13 @@ func (head *lfstack) pop() unsafe.Pointer {
 func (head *lfstack) empty() bool {
 	return atomic.Load64((*uint64)(head)) == 0
 }
+
+// lfnodeValidate panics if node is not a valid address for use with
+// lfstack.push. This only needs to be called when node is allocated.
+func lfnodeValidate(node *lfnode) {
+	if lfstackUnpack(lfstackPack(node, ^uintptr(0))) != node {
+		printlock()
+		println("runtime: bad lfnode address", hex(uintptr(unsafe.Pointer(node))))
+		throw("bad lfnode address")
+	}
+}