diff --git a/sys/kern/kern_sig.c b/sys/kern/kern_sig.c
index a4f0f889005c..06d8e9924f85 100644
--- a/sys/kern/kern_sig.c
+++ b/sys/kern/kern_sig.c
@@ -653,9 +653,10 @@ kern_sigaction(td, sig, act, oact, flags)
 
 	if (!_SIG_VALID(sig))
 		return (EINVAL);
-	if (act != NULL && (act->sa_flags & ~(SA_ONSTACK | SA_RESTART |
-	    SA_RESETHAND | SA_NOCLDSTOP | SA_NODEFER | SA_NOCLDWAIT |
-	    SA_SIGINFO)) != 0)
+	if (act != NULL && act->sa_handler != SIG_DFL &&
+	    act->sa_handler != SIG_IGN && (act->sa_flags & ~(SA_ONSTACK |
+	    SA_RESTART | SA_RESETHAND | SA_NOCLDSTOP | SA_NODEFER |
+	    SA_NOCLDWAIT | SA_SIGINFO)) != 0)
 		return (EINVAL);
 
 	PROC_LOCK(p);