diff --git a/arch/alpha/kernel/signal.c b/arch/alpha/kernel/signal.c
index d290845aef59..6f7feb5db271 100644
--- a/arch/alpha/kernel/signal.c
+++ b/arch/alpha/kernel/signal.c
@@ -48,7 +48,7 @@ SYSCALL_DEFINE2(osf_sigprocmask, int, how, unsigned long, newmask)
 	sigset_t mask;
 	unsigned long res;
 
-	siginitset(&mask, newmask & ~_BLOCKABLE);
+	siginitset(&mask, newmask & _BLOCKABLE);
 	res = sigprocmask(how, &mask, &oldmask);
 	if (!res) {
 		force_successful_syscall_return();