syncs: start working on mutex debugging, registrationbradfitz/mutex_debug

Updates #17852

Change-Id: Ib1b634eedd30cc4006bc1b39aa8d479d37c5f1f2
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>

2 files changed, 4 insertions, 1 deletions

diff --git a/control/controlbase/conn.go b/control/controlbase/conn.go
index 78ef73f71..8a3a90495 100644
--- a/control/controlbase/conn.go
+++ b/control/controlbase/conn.go
@@ -61,7 +61,7 @@ type rxState struct {
 
 // txState is all the Conn state that Write uses.
 type txState struct {
-	sync.Mutex
+	syncs.Mutex
 	cipher cipher.AEAD
 	nonce  nonce
 	err    error // records the first partial write error for all future calls
diff --git a/control/controlbase/handshake.go b/control/controlbase/handshake.go
index 765a4620b..a57a3eca3 100644
--- a/control/controlbase/handshake.go
+++ b/control/controlbase/handshake.go
@@ -20,6 +20,7 @@ import (
 	chp "golang.org/x/crypto/chacha20poly1305"
 	"golang.org/x/crypto/curve25519"
 	"golang.org/x/crypto/hkdf"
+	"tailscale.com/syncs"
 	"tailscale.com/types/key"
 )
 
@@ -186,6 +187,8 @@ func continueClientHandshake(ctx context.Context, conn net.Conn, s *symmetricSta
 			cipher: c2,
 		},
 	}
+	syncs.RegisterMutex(&c.rx.Mutex, "controlbase.Conn.rx.Mutex")
+	syncs.RegisterMutex(&c.tx.Mutex, "controlbase.Conn.tx.Mutex")
 	return c, nil
 }