4 files changed, 60 insertions, 24 deletions
diff --git a/src/runtime/export_test.go b/src/runtime/export_test.go
index a48bb2636f..5a87024b8a 100644
--- a/src/runtime/export_test.go
+++ b/src/runtime/export_test.go
@@ -46,6 +46,14 @@ var NetpollGenericInit = netpollGenericInit
 var Memmove = memmove
 var MemclrNoHeapPointers = memclrNoHeapPointers
 
+var LockPartialOrder = lockPartialOrder
+
+type LockRank lockRank
+
+func (l LockRank) String() string {
+	return lockRank(l).String()
+}
+
 const PreemptMSupported = preemptMSupported
 
 type LFNode struct {
diff --git a/src/runtime/lockrank.go b/src/runtime/lockrank.go
index 5a908b470f..b600c2132b 100644
--- a/src/runtime/lockrank.go
+++ b/src/runtime/lockrank.go
@@ -204,7 +204,7 @@ var lockPartialOrder [][]lockRank = [][]lockRank{
 	lockRankDeadlock:      {lockRankDeadlock},
 	lockRankAllg:          {lockRankSysmon, lockRankSched},
 	lockRankAllp:          {lockRankSysmon, lockRankSched},
-	lockRankTimers:        {lockRankSysmon, lockRankScavenge, lockRankSched, lockRankAllp, lockRankPollDesc, lockRankTimers},
+	lockRankTimers:        {lockRankSysmon, lockRankScavenge, lockRankPollDesc, lockRankSched, lockRankAllp, lockRankTimers},
 	lockRankItab:          {},
 	lockRankReflectOffs:   {lockRankItab},
 	lockRankHchan:         {lockRankScavenge, lockRankSweep, lockRankHchan},
@@ -213,25 +213,25 @@ var lockPartialOrder [][]lockRank = [][]lockRank{
 	lockRankTraceBuf:      {lockRankSysmon, lockRankScavenge},
 	lockRankTraceStrings:  {lockRankTraceBuf},
 	lockRankMspanSpecial:  {lockRankSysmon, lockRankScavenge, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankItab, lockRankReflectOffs, lockRankHchan, lockRankNotifyList, lockRankTraceBuf, lockRankTraceStrings},
-	lockRankProf:          {lockRankSysmon, lockRankScavenge, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankItab, lockRankReflectOffs, lockRankNotifyList, lockRankTraceBuf, lockRankTraceStrings, lockRankHchan},
-	lockRankGcBitsArenas:  {lockRankSysmon, lockRankScavenge, lockRankAssistQueue, lockRankCpuprof, lockRankSched, lockRankAllg, lockRankTimers, lockRankItab, lockRankReflectOffs, lockRankNotifyList, lockRankTraceBuf, lockRankTraceStrings, lockRankHchan},
+	lockRankProf:          {lockRankSysmon, lockRankScavenge, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankItab, lockRankReflectOffs, lockRankHchan, lockRankNotifyList, lockRankTraceBuf, lockRankTraceStrings},
+	lockRankGcBitsArenas:  {lockRankSysmon, lockRankScavenge, lockRankAssistQueue, lockRankCpuprof, lockRankSched, lockRankAllg, lockRankTimers, lockRankItab, lockRankReflectOffs, lockRankHchan, lockRankNotifyList, lockRankTraceBuf, lockRankTraceStrings},
 	lockRankRoot:          {},
-	lockRankTrace:         {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankAssistQueue, lockRankSched, lockRankHchan, lockRankTraceBuf, lockRankTraceStrings, lockRankRoot, lockRankSweep},
+	lockRankTrace:         {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankAssistQueue, lockRankSweep, lockRankSched, lockRankHchan, lockRankTraceBuf, lockRankTraceStrings, lockRankRoot},
 	lockRankTraceStackTab: {lockRankScavenge, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankSched, lockRankAllg, lockRankTimers, lockRankHchan, lockRankFin, lockRankNotifyList, lockRankTraceBuf, lockRankTraceStrings, lockRankRoot, lockRankTrace},
 	lockRankNetpollInit:   {lockRankTimers},
 
 	lockRankRwmutexW: {},
 	lockRankRwmutexR: {lockRankSysmon, lockRankRwmutexW},
 
-	lockRankSpanSetSpine: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankPollDesc, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankItab, lockRankReflectOffs, lockRankNotifyList, lockRankTraceBuf, lockRankTraceStrings, lockRankHchan},
-	lockRankGscan:        {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankPollDesc, lockRankSched, lockRankTimers, lockRankItab, lockRankReflectOffs, lockRankHchan, lockRankFin, lockRankTraceBuf, lockRankTraceStrings, lockRankRoot, lockRankNotifyList, lockRankProf, lockRankGcBitsArenas, lockRankTrace, lockRankTraceStackTab, lockRankNetpollInit, lockRankSpanSetSpine},
-	lockRankStackpool:    {lockRankSysmon, lockRankScavenge, lockRankSweepWaiters, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankSched, lockRankPollDesc, lockRankTimers, lockRankItab, lockRankReflectOffs, lockRankHchan, lockRankFin, lockRankNotifyList, lockRankTraceBuf, lockRankTraceStrings, lockRankProf, lockRankGcBitsArenas, lockRankRoot, lockRankTrace, lockRankTraceStackTab, lockRankNetpollInit, lockRankRwmutexR, lockRankSpanSetSpine, lockRankGscan},
+	lockRankSpanSetSpine: {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankPollDesc, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankItab, lockRankReflectOffs, lockRankHchan, lockRankNotifyList, lockRankTraceBuf, lockRankTraceStrings},
+	lockRankGscan:        {lockRankSysmon, lockRankScavenge, lockRankForcegc, lockRankSweepWaiters, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankPollDesc, lockRankSched, lockRankTimers, lockRankItab, lockRankReflectOffs, lockRankHchan, lockRankFin, lockRankNotifyList, lockRankTraceBuf, lockRankTraceStrings, lockRankProf, lockRankGcBitsArenas, lockRankRoot, lockRankTrace, lockRankTraceStackTab, lockRankNetpollInit, lockRankSpanSetSpine},
+	lockRankStackpool:    {lockRankSysmon, lockRankScavenge, lockRankSweepWaiters, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankPollDesc, lockRankSched, lockRankTimers, lockRankItab, lockRankReflectOffs, lockRankHchan, lockRankFin, lockRankNotifyList, lockRankTraceBuf, lockRankTraceStrings, lockRankProf, lockRankGcBitsArenas, lockRankRoot, lockRankTrace, lockRankTraceStackTab, lockRankNetpollInit, lockRankRwmutexR, lockRankSpanSetSpine, lockRankGscan},
 	lockRankStackLarge:   {lockRankSysmon, lockRankAssistQueue, lockRankSched, lockRankItab, lockRankHchan, lockRankProf, lockRankGcBitsArenas, lockRankRoot, lockRankSpanSetSpine, lockRankGscan},
 	lockRankDefer:        {},
-	lockRankSudog:        {lockRankNotifyList, lockRankHchan},
-	lockRankWbufSpans:    {lockRankSysmon, lockRankScavenge, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankSched, lockRankAllg, lockRankPollDesc, lockRankTimers, lockRankItab, lockRankReflectOffs, lockRankHchan, lockRankFin, lockRankNotifyList, lockRankTraceStrings, lockRankMspanSpecial, lockRankProf, lockRankRoot, lockRankGscan, lockRankDefer, lockRankSudog},
-	lockRankMheap:        {lockRankSysmon, lockRankScavenge, lockRankSweepWaiters, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankPollDesc, lockRankSched, lockRankAllg, lockRankAllp, lockRankFin, lockRankTimers, lockRankItab, lockRankReflectOffs, lockRankNotifyList, lockRankTraceBuf, lockRankTraceStrings, lockRankHchan, lockRankMspanSpecial, lockRankProf, lockRankGcBitsArenas, lockRankRoot, lockRankGscan, lockRankStackpool, lockRankStackLarge, lockRankDefer, lockRankSudog, lockRankWbufSpans, lockRankSpanSetSpine},
-	lockRankMheapSpecial: {lockRankSysmon, lockRankScavenge, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankPollDesc, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankItab, lockRankReflectOffs, lockRankNotifyList, lockRankTraceBuf, lockRankTraceStrings, lockRankHchan},
+	lockRankSudog:        {lockRankHchan, lockRankNotifyList},
+	lockRankWbufSpans:    {lockRankSysmon, lockRankScavenge, lockRankSweepWaiters, lockRankAssistQueue, lockRankSweep, lockRankPollDesc, lockRankSched, lockRankAllg, lockRankTimers, lockRankItab, lockRankReflectOffs, lockRankHchan, lockRankFin, lockRankNotifyList, lockRankTraceStrings, lockRankMspanSpecial, lockRankProf, lockRankRoot, lockRankGscan, lockRankDefer, lockRankSudog},
+	lockRankMheap:        {lockRankSysmon, lockRankScavenge, lockRankSweepWaiters, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankPollDesc, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankItab, lockRankReflectOffs, lockRankHchan, lockRankFin, lockRankNotifyList, lockRankTraceBuf, lockRankTraceStrings, lockRankMspanSpecial, lockRankProf, lockRankGcBitsArenas, lockRankRoot, lockRankSpanSetSpine, lockRankGscan, lockRankStackpool, lockRankStackLarge, lockRankDefer, lockRankSudog, lockRankWbufSpans},
+	lockRankMheapSpecial: {lockRankSysmon, lockRankScavenge, lockRankAssistQueue, lockRankCpuprof, lockRankSweep, lockRankPollDesc, lockRankSched, lockRankAllg, lockRankAllp, lockRankTimers, lockRankItab, lockRankReflectOffs, lockRankHchan, lockRankNotifyList, lockRankTraceBuf, lockRankTraceStrings},
 	lockRankGlobalAlloc:  {lockRankProf, lockRankSpanSetSpine, lockRankMheap, lockRankMheapSpecial},
 
 	lockRankGFree:     {lockRankSched},
diff --git a/src/runtime/lockrank_on.go b/src/runtime/lockrank_on.go
index 3958d9eeaa..fc8d2dc8d1 100644
--- a/src/runtime/lockrank_on.go
+++ b/src/runtime/lockrank_on.go
@@ -25,19 +25,6 @@ type lockRankStruct struct {
 	pad int
 }
 
-// init checks that the partial order in lockPartialOrder fits within the total
-// order determined by the order of the lockRank constants.
-func init() {
-	for rank, list := range lockPartialOrder {
-		for _, entry := range list {
-			if entry > lockRank(rank) {
-				println("lockPartial order row", lockRank(rank).String(), "entry", entry.String())
-				throw("lockPartialOrder table is inconsistent with total lock ranking order")
-			}
-		}
-	}
-}
-
 func lockInit(l *mutex, rank lockRank) {
 	l.rank = rank
 }
diff --git a/src/runtime/lockrank_test.go b/src/runtime/lockrank_test.go
new file mode 100644
index 0000000000..4b2fc0eaee
--- /dev/null
+++ b/src/runtime/lockrank_test.go
@@ -0,0 +1,41 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package runtime_test
+
+import (
+	. "runtime"
+	"testing"
+)
+
+// Check that the partial order in lockPartialOrder fits within the total order
+// determined by the order of the lockRank constants.
+func TestLockRankPartialOrder(t *testing.T) {
+	for r, list := range LockPartialOrder {
+		rank := LockRank(r)
+		for _, e := range list {
+			entry := LockRank(e)
+			if entry > rank {
+				t.Errorf("lockPartialOrder row %v entry %v is inconsistent with total lock ranking order", rank, entry)
+			}
+		}
+	}
+}
+
+// Verify that partial order lists are kept sorted. This is a purely cosemetic
+// check to make manual reviews simpler. It does not affect correctness, unlike
+// the above test.
+func TestLockRankPartialOrderSortedEntries(t *testing.T) {
+	for r, list := range LockPartialOrder {
+		rank := LockRank(r)
+		var prev LockRank
+		for _, e := range list {
+			entry := LockRank(e)
+			if entry <= prev {
+				t.Errorf("Partial order for rank %v out of order: %v <= %v in %v", rank, entry, prev, list)
+			}
+			prev = entry
+		}
+	}
+}