wgengine/magicsock: fix relayManager deadlock (#17449)

Updates tailscale/corp#32978 Signed-off-by: Jordan Whited <jordan@tailscale.com>
2025-10-04 20:27:57 -07:00
parent 3aa8b6d683
commit e44e28efcd
2 changed files with 43 additions and 1 deletions
@@ -758,7 +758,10 @@ func (r *relayManager) handleNewServerEndpointRunLoop(newServerEndpoint newRelay
 		ctx:          ctx,
 		cancel:       cancel,
 	}
-	if byServerDisco == nil {
+	// We must look up byServerDisco again. The previous value may have been
+	// deleted from the outer map when cleaning up duplicate work.
+	byServerDisco, ok = r.handshakeWorkByServerDiscoByEndpoint[newServerEndpoint.wlb.ep]
+	if !ok {
 		byServerDisco = make(map[key.DiscoPublic]*relayHandshakeWork)
 		r.handshakeWorkByServerDiscoByEndpoint[newServerEndpoint.wlb.ep] = byServerDisco
 	}