diff --git a/lib/BuildSystem/LaneBasedExecutionQueue.cpp b/lib/BuildSystem/LaneBasedExecutionQueue.cpp
index 7f0e83ad..69bea512 100644
--- a/lib/BuildSystem/LaneBasedExecutionQueue.cpp
+++ b/lib/BuildSystem/LaneBasedExecutionQueue.cpp
@@ -159,10 +159,12 @@ class LaneBasedExecutionQueue : public BuildExecutionQueue {
     }
     posix_spawnattr_setsigdefault(&attributes, &mostSignals);
 #else
-    sigset_t allSignals;
-    sigfillset(&allSignals);
-    posix_spawnattr_setsigdefault(&attributes, &allSignals);
-#endif      
+    sigset_t mostSignals;
+    sigfillset(&mostSignals);
+    sigdelset(&mostSignals, SIGKILL);
+    sigdelset(&mostSignals, SIGSTOP);
+    posix_spawnattr_setsigdefault(&attributes, &mostSignals);
+#endif
 
     // Establish a separate process group.
     posix_spawnattr_setpgroup(&attributes, 0);
diff --git a/lib/Commands/NinjaBuildCommand.cpp b/lib/Commands/NinjaBuildCommand.cpp
index 5b8ac09a..a00d7d8a 100644
--- a/lib/Commands/NinjaBuildCommand.cpp
+++ b/lib/Commands/NinjaBuildCommand.cpp
@@ -1169,9 +1169,11 @@ buildCommand(BuildContext& context, ninja::Command* command) {
       }
       posix_spawnattr_setsigdefault(&attributes, &mostSignals);
 #else
-      sigset_t allSignals;
-      sigfillset(&allSignals);
-      posix_spawnattr_setsigdefault(&attributes, &allSignals);
+      sigset_t mostSignals;
+      sigfillset(&mostSignals);
+      sigdelset(&mostSignals, SIGKILL);
+      sigdelset(&mostSignals, SIGSTOP);
+      posix_spawnattr_setsigdefault(&attributes, &mostSignals);
 #endif
 
       // Establish a separate process group.