diff --git a/src/runtime/panic.go b/src/runtime/panic.go
index 9e108cc437..f78e67f9bb 100644
--- a/src/runtime/panic.go
+++ b/src/runtime/panic.go
@@ -576,6 +576,11 @@ func dopanic(unused int) {
 	*(*int)(nil) = 0
 }
 
+//go:linkname sync_throw sync.throw
+func sync_throw(s string) {
+	throw(s)
+}
+
 //go:nosplit
 func throw(s string) {
 	print("fatal error: ", s, "\n")
diff --git a/src/sync/mutex.go b/src/sync/mutex.go
index 90892793f0..717934344e 100644
--- a/src/sync/mutex.go
+++ b/src/sync/mutex.go
@@ -16,6 +16,8 @@ import (
 	"unsafe"
 )
 
+func throw(string) // provided by runtime
+
 // A Mutex is a mutual exclusion lock.
 // Mutexes can be created as part of other structures;
 // the zero value for a Mutex is an unlocked mutex.
@@ -74,7 +76,7 @@ func (m *Mutex) Lock() {
 			// The goroutine has been woken from sleep,
 			// so we need to reset the flag in either case.
 			if new&mutexWoken == 0 {
-				panic("sync: inconsistent mutex state")
+				throw("sync: inconsistent mutex state")
 			}
 			new &^= mutexWoken
 		}
@@ -108,7 +110,7 @@ func (m *Mutex) Unlock() {
 	// Fast path: drop lock bit.
 	new := atomic.AddInt32(&m.state, -mutexLocked)
 	if (new+mutexLocked)&mutexLocked == 0 {
-		panic("sync: unlock of unlocked mutex")
+		throw("sync: unlock of unlocked mutex")
 	}
 
 	old := new
diff --git a/src/sync/mutex_test.go b/src/sync/mutex_test.go
index 91a4855cb1..fbfe4b77fe 100644
--- a/src/sync/mutex_test.go
+++ b/src/sync/mutex_test.go
@@ -7,7 +7,12 @@
 package sync_test
 
 import (
+	"fmt"
+	"internal/testenv"
+	"os"
+	"os/exec"
 	"runtime"
+	"strings"
 	. "sync"
 	"testing"
 )
@@ -71,17 +76,98 @@ func TestMutex(t *testing.T) {
 	}
 }
 
-func TestMutexPanic(t *testing.T) {
-	defer func() {
-		if recover() == nil {
-			t.Fatalf("unlock of unlocked mutex did not panic")
-		}
-	}()
+var misuseTests = []struct {
+	name string
+	f    func()
+}{
+	{
+		"Mutex.Unlock",
+		func() {
+			var mu Mutex
+			mu.Unlock()
+		},
+	},
+	{
+		"Mutex.Unlock2",
+		func() {
+			var mu Mutex
+			mu.Lock()
+			mu.Unlock()
+			mu.Unlock()
+		},
+	},
+	{
+		"RWMutex.Unlock",
+		func() {
+			var mu RWMutex
+			mu.Unlock()
+		},
+	},
+	{
+		"RWMutex.Unlock2",
+		func() {
+			var mu RWMutex
+			mu.RLock()
+			mu.Unlock()
+		},
+	},
+	{
+		"RWMutex.Unlock3",
+		func() {
+			var mu RWMutex
+			mu.Lock()
+			mu.Unlock()
+			mu.Unlock()
+		},
+	},
+	{
+		"RWMutex.RUnlock",
+		func() {
+			var mu RWMutex
+			mu.RUnlock()
+		},
+	},
+	{
+		"RWMutex.RUnlock2",
+		func() {
+			var mu RWMutex
+			mu.Lock()
+			mu.RUnlock()
+		},
+	},
+	{
+		"RWMutex.RUnlock3",
+		func() {
+			var mu RWMutex
+			mu.RLock()
+			mu.RUnlock()
+			mu.RUnlock()
+		},
+	},
+}
 
-	var mu Mutex
-	mu.Lock()
-	mu.Unlock()
-	mu.Unlock()
+func init() {
+	if len(os.Args) == 3 && os.Args[1] == "TESTMISUSE" {
+		for _, test := range misuseTests {
+			if test.name == os.Args[2] {
+				test.f()
+				fmt.Printf("test completed\n")
+				os.Exit(0)
+			}
+		}
+		fmt.Printf("unknown test\n")
+		os.Exit(0)
+	}
+}
+
+func TestMutexMisuse(t *testing.T) {
+	testenv.MustHaveExec(t)
+	for _, test := range misuseTests {
+		out, err := exec.Command(os.Args[0], "TESTMISUSE", test.name).CombinedOutput()
+		if err == nil || !strings.Contains(string(out), "unlocked") {
+			t.Errorf("%s: did not find failure with message about unlocked lock: %s\n%s\n", test.name, err, out)
+		}
+	}
 }
 
 func BenchmarkMutexUncontended(b *testing.B) {
diff --git a/src/sync/rwmutex.go b/src/sync/rwmutex.go
index 6734360e37..71064eeeba 100644
--- a/src/sync/rwmutex.go
+++ b/src/sync/rwmutex.go
@@ -61,7 +61,7 @@ func (rw *RWMutex) RUnlock() {
 	if r := atomic.AddInt32(&rw.readerCount, -1); r < 0 {
 		if r+1 == 0 || r+1 == -rwmutexMaxReaders {
 			race.Enable()
-			panic("sync: RUnlock of unlocked RWMutex")
+			throw("sync: RUnlock of unlocked RWMutex")
 		}
 		// A writer is pending.
 		if atomic.AddInt32(&rw.readerWait, -1) == 0 {
@@ -115,7 +115,7 @@ func (rw *RWMutex) Unlock() {
 	r := atomic.AddInt32(&rw.readerCount, rwmutexMaxReaders)
 	if r >= rwmutexMaxReaders {
 		race.Enable()
-		panic("sync: Unlock of unlocked RWMutex")
+		throw("sync: Unlock of unlocked RWMutex")
 	}
 	// Unblock blocked readers, if any.
 	for i := 0; i < int(r); i++ {
diff --git a/src/sync/rwmutex_test.go b/src/sync/rwmutex_test.go
index f625bc3a58..0436f97239 100644
--- a/src/sync/rwmutex_test.go
+++ b/src/sync/rwmutex_test.go
@@ -155,48 +155,6 @@ func TestRLocker(t *testing.T) {
 	}
 }
 
-func TestUnlockPanic(t *testing.T) {
-	defer func() {
-		if recover() == nil {
-			t.Fatalf("unlock of unlocked RWMutex did not panic")
-		}
-	}()
-	var mu RWMutex
-	mu.Unlock()
-}
-
-func TestUnlockPanic2(t *testing.T) {
-	defer func() {
-		if recover() == nil {
-			t.Fatalf("unlock of unlocked RWMutex did not panic")
-		}
-	}()
-	var mu RWMutex
-	mu.RLock()
-	mu.Unlock()
-}
-
-func TestRUnlockPanic(t *testing.T) {
-	defer func() {
-		if recover() == nil {
-			t.Fatalf("read unlock of unlocked RWMutex did not panic")
-		}
-	}()
-	var mu RWMutex
-	mu.RUnlock()
-}
-
-func TestRUnlockPanic2(t *testing.T) {
-	defer func() {
-		if recover() == nil {
-			t.Fatalf("read unlock of unlocked RWMutex did not panic")
-		}
-	}()
-	var mu RWMutex
-	mu.Lock()
-	mu.RUnlock()
-}
-
 func BenchmarkRWMutexUncontended(b *testing.B) {
 	type PaddedRWMutex struct {
 		RWMutex