diff --git a/src/runtime/malloc.go b/src/runtime/malloc.go
index f8d5d48a28..7affe244a2 100644
--- a/src/runtime/malloc.go
+++ b/src/runtime/malloc.go
@@ -972,7 +972,7 @@ func mallocgc(size uintptr, typ *_type, needzero bool) unsafe.Pointer {
 
 	shouldhelpgc := false
 	dataSize := size
-	c := getMCache()
+	c := getMCache(mp)
 	if c == nil {
 		throw("mallocgc called without a P or outside bootstrapping")
 	}
@@ -1247,7 +1247,7 @@ func reflect_unsafe_NewArray(typ *_type, n int) unsafe.Pointer {
 }
 
 func profilealloc(mp *m, x unsafe.Pointer, size uintptr) {
-	c := getMCache()
+	c := getMCache(mp)
 	if c == nil {
 		throw("profilealloc called without a P or outside bootstrapping")
 	}
diff --git a/src/runtime/mcache.go b/src/runtime/mcache.go
index a9e959109a..21c36ca750 100644
--- a/src/runtime/mcache.go
+++ b/src/runtime/mcache.go
@@ -122,9 +122,9 @@ func freemcache(c *mcache) {
 //
 // Returns nil if we're not bootstrapping or we don't have a P. The caller's
 // P must not change, so we must be in a non-preemptible state.
-func getMCache() *mcache {
+func getMCache(mp *m) *mcache {
 	// Grab the mcache, since that's where stats live.
-	pp := getg().m.p.ptr()
+	pp := mp.p.ptr()
 	var c *mcache
 	if pp == nil {
 		// We will be called without a P while bootstrapping,