diff --git a/ChangeLog b/ChangeLog
index 8f3924d742..60f4e60db0 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2019-01-24  Samuel Thibault  <samuel.thibault@ens-lyon.org>
+
+	* hurd/hurdsig.c (_hurd_thread_sigstate): Set SS_DISABLE in
+	sigaltstack.ss_flags.
+
 2019-01-24  TAMUKI Shoichi  <tamuki@linet.gr.jp>
 
 	[BZ #23758]
diff --git a/hurd/hurdsig.c b/hurd/hurdsig.c
index 1d9516a2f7..1e4b3466ce 100644
--- a/hurd/hurdsig.c
+++ b/hurd/hurdsig.c
@@ -92,6 +92,7 @@ _hurd_thread_sigstate (thread_t thread)
       __sigemptyset (&ss->blocked);
       __sigemptyset (&ss->pending);
       memset (&ss->sigaltstack, 0, sizeof (ss->sigaltstack));
+      ss->sigaltstack.ss_flags |= SS_DISABLE;
       ss->preemptors = NULL;
       ss->suspended = MACH_PORT_NULL;
       ss->intr_port = MACH_PORT_NULL;