runtime: avoid fault in heapBitsBulkBarrier

Change-Id: I0512e461de1f25cb2a1cb7f23e7a77d00700667c
Reviewed-on: https://go-review.googlesource.com/10803
Reviewed-by: Russ Cox <rsc@golang.org>

diff --git a/src/runtime/mbitmap.go b/src/runtime/mbitmap.go
index 11bfcd1b276bc0cb8fcb1dc1ca98de1f7dae305c..a4090b9a087dae81c9c33674e85453b3f0e38597 100644 (file)
--- a/src/runtime/mbitmap.go
+++ b/src/runtime/mbitmap.go
@@ -388,7 +388,7 @@ func heapBitsBulkBarrier(p, size uintptr) {
                // unwinding the stack barriers between the current SP
                // and p's frame.
                gp := getg().m.curg
-               if gp.stack.lo <= p && p < gp.stack.hi {
+               if gp != nil && gp.stack.lo <= p && p < gp.stack.hi {
                        // Run on the system stack to give it more
                        // stack space.
                        systemstack(func() {