diff --git a/fs/fcntl.c b/fs/fcntl.c
index 3e7ab16..286a9f8 100644
--- a/fs/fcntl.c
+++ b/fs/fcntl.c
@@ -15,6 +15,7 @@
 #include <linux/module.h>
 #include <linux/security.h>
 #include <linux/ptrace.h>
+#include <linux/signal.h>
 
 #include <asm/poll.h>
 #include <asm/siginfo.h>
@@ -308,7 +309,7 @@
 		break;
 	case F_SETSIG:
 		/* arg == 0 restores default behaviour. */
-		if (arg < 0 || arg > _NSIG) {
+		if (!valid_signal(arg)) {
 			break;
 		}
 		err = 0;