diff --git a/src/liblwevent/400_signalfd.c b/src/liblwevent/400_signalfd.c
index 264e1fa..83df7e0 100644
--- a/src/liblwevent/400_signalfd.c
+++ b/src/liblwevent/400_signalfd.c
@@ -7,11 +7,14 @@
 
 
 
+#define SIZEOF_SIG (_NSIG / 8)
+#define SIZEOF_SIGSET (SIZEOF_SIG > sizeof(sigset_t) ? sizeof(sigset_t): SIZEOF_SIG)
+
+
+
 int signalfd(int fd, const sigset_t* mask)
 {
-    size_t sz;
-    sz = sizeof(sigset_t);
-    return syscall(__NR_signalfd, fd, mask, sz);
+    return syscall(__NR_signalfd, fd, mask, SIZEOF_SIGSET);
 }
 
 
@@ -73,6 +76,8 @@ struct lwevent_signal* lwevent_signalfd(const sigset_t* mask, lwevent_signalcb c
         return 0;
     }
 
+    TEMP_FAILURE_RETRY( sigprocmask(SIG_BLOCK, &si->mask, 0) );
+
     lwevent_set_user(si->ev, si);
     return si;
 }