diff --git a/src/inspector_agent.cc b/src/inspector_agent.cc
index 5e53201c42d5c2..21319abca7d1f5 100644
--- a/src/inspector_agent.cc
+++ b/src/inspector_agent.cc
@@ -110,7 +110,9 @@ static int StartDebugSignalHandler() {
   sigset_t sigmask;
   // Mask all signals.
   sigfillset(&sigmask);
-  CHECK_EQ(0, pthread_sigmask(SIG_SETMASK, &sigmask, &sigmask));
+  sigset_t savemask;
+  CHECK_EQ(0, pthread_sigmask(SIG_SETMASK, &sigmask, &savemask));
+  sigmask = savemask;
   pthread_t thread;
   const int err = pthread_create(&thread, &attr,
                                  StartIoThreadMain, nullptr);
diff --git a/src/node_watchdog.cc b/src/node_watchdog.cc
index b8665dc1be225d..9ef7bafeded44f 100644
--- a/src/node_watchdog.cc
+++ b/src/node_watchdog.cc
@@ -187,7 +187,9 @@ int SigintWatchdogHelper::Start() {
 
   sigset_t sigmask;
   sigfillset(&sigmask);
-  CHECK_EQ(0, pthread_sigmask(SIG_SETMASK, &sigmask, &sigmask));
+  sigset_t savemask;
+  CHECK_EQ(0, pthread_sigmask(SIG_SETMASK, &sigmask, &savemask));
+  sigmask = savemask;
   int ret = pthread_create(&thread_, nullptr, RunSigintWatchdog, nullptr);
   CHECK_EQ(0, pthread_sigmask(SIG_SETMASK, &sigmask, nullptr));
   if (ret != 0) {