diff --git a/sys/compat/linux/common/linux_sched.c b/sys/compat/linux/common/linux_sched.c
index bfa5d592cfa0..f35fc18ef13e 100644
--- a/sys/compat/linux/common/linux_sched.c
+++ b/sys/compat/linux/common/linux_sched.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: linux_sched.c,v 1.68 2015/07/03 02:24:28 christos Exp $	*/
+/*	$NetBSD: linux_sched.c,v 1.69 2017/04/21 15:10:34 christos Exp $	*/
 
 /*-
  * Copyright (c) 1999 The NetBSD Foundation, Inc.
@@ -35,7 +35,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: linux_sched.c,v 1.68 2015/07/03 02:24:28 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: linux_sched.c,v 1.69 2017/04/21 15:10:34 christos Exp $");
 
 #include <sys/param.h>
 #include <sys/mount.h>
@@ -207,7 +207,8 @@ linux_clone_nptl(struct lwp *l, const struct linux_sys_clone_args *uap, register
 	}
 
 	error = lwp_create(l, p, uaddr, LWP_DETACHED | LWP_PIDLID,
-	    SCARG(uap, stack), 0, child_return, NULL, &l2, l->l_class);
+	    SCARG(uap, stack), 0, child_return, NULL, &l2, l->l_class,
+	    &l->l_sigmask, &l->l_sigstk);
 	if (__predict_false(error)) {
 		DPRINTF(("%s: lwp_create error=%d\n", __func__, error));
 		atomic_dec_uint(&nprocs);
diff --git a/sys/compat/netbsd32/netbsd32_lwp.c b/sys/compat/netbsd32/netbsd32_lwp.c
index e0a202f70bf2..20cb44270263 100644
--- a/sys/compat/netbsd32/netbsd32_lwp.c
+++ b/sys/compat/netbsd32/netbsd32_lwp.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: netbsd32_lwp.c,v 1.18 2015/05/15 07:56:25 matt Exp $	*/
+/*	$NetBSD: netbsd32_lwp.c,v 1.19 2017/04/21 15:10:34 christos Exp $	*/
 
 /*
  *  Copyright (c) 2005, 2006, 2007 The NetBSD Foundation.
@@ -27,7 +27,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: netbsd32_lwp.c,v 1.18 2015/05/15 07:56:25 matt Exp $");
+__KERNEL_RCSID(0, "$NetBSD: netbsd32_lwp.c,v 1.19 2017/04/21 15:10:34 christos Exp $");
 
 #include <sys/types.h>
 #include <sys/param.h>
@@ -74,7 +74,11 @@ netbsd32__lwp_create(struct lwp *l, const struct netbsd32__lwp_create_args *uap,
 	if (error)
 		goto fail;
 
-	error = do_lwp_create(l, newuc, SCARG(uap, flags), &lid);
+	const sigset_t *sigmask = newuc->uc_flags & _UC_SIGMASK ?
+	    &newuc->uc_sigmask : &l->l_sigmask;
+
+	error = do_lwp_create(l, newuc, SCARG(uap, flags), &lid, sigmask,
+	    &SS_INIT);
 	if (error)
 		goto fail;
 
diff --git a/sys/kern/kern_exec.c b/sys/kern/kern_exec.c
index 8ea6fcf192c1..e288a5d4383c 100644
--- a/sys/kern/kern_exec.c
+++ b/sys/kern/kern_exec.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: kern_exec.c,v 1.441 2017/01/25 17:57:14 christos Exp $	*/
+/*	$NetBSD: kern_exec.c,v 1.442 2017/04/21 15:10:34 christos Exp $	*/
 
 /*-
  * Copyright (c) 2008 The NetBSD Foundation, Inc.
@@ -59,7 +59,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_exec.c,v 1.441 2017/01/25 17:57:14 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_exec.c,v 1.442 2017/04/21 15:10:34 christos Exp $");
 
 #include "opt_exec.h"
 #include "opt_execfmt.h"
@@ -2531,7 +2531,7 @@ do_posix_spawn(struct lwp *l1, pid_t *pid_res, bool *child_ok, const char *path,
 
 	/* create LWP */
 	lwp_create(l1, p2, uaddr, 0, NULL, 0, spawn_return, spawn_data,
-	    &l2, l1->l_class);
+	    &l2, l1->l_class, &l1->l_sigmask, &l1->l_sigstk);
 	l2->l_ctxlink = NULL;	/* reset ucontext link */
 
 	/*
diff --git a/sys/kern/kern_fork.c b/sys/kern/kern_fork.c
index 8c2b87755117..64db03264014 100644
--- a/sys/kern/kern_fork.c
+++ b/sys/kern/kern_fork.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: kern_fork.c,v 1.201 2017/03/31 08:50:54 skrll Exp $	*/
+/*	$NetBSD: kern_fork.c,v 1.202 2017/04/21 15:10:34 christos Exp $	*/
 
 /*-
  * Copyright (c) 1999, 2001, 2004, 2006, 2007, 2008 The NetBSD Foundation, Inc.
@@ -67,7 +67,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_fork.c,v 1.201 2017/03/31 08:50:54 skrll Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_fork.c,v 1.202 2017/04/21 15:10:34 christos Exp $");
 
 #include "opt_ktrace.h"
 #include "opt_dtrace.h"
@@ -434,7 +434,7 @@ fork1(struct lwp *l1, int flags, int exitsig, void *stack, size_t stacksize,
 	 */
 	lwp_create(l1, p2, uaddr, (flags & FORK_PPWAIT) ? LWP_VFORK : 0,
 	    stack, stacksize, (func != NULL) ? func : child_return, arg, &l2,
-	    l1->l_class);
+	    l1->l_class, &l1->l_sigmask, &l1->l_sigstk);
 
 	/*
 	 * Inherit l_private from the parent.
diff --git a/sys/kern/kern_kthread.c b/sys/kern/kern_kthread.c
index f575262f0816..d8ad0e8a65f6 100644
--- a/sys/kern/kern_kthread.c
+++ b/sys/kern/kern_kthread.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: kern_kthread.c,v 1.41 2015/04/21 11:10:29 pooka Exp $	*/
+/*	$NetBSD: kern_kthread.c,v 1.42 2017/04/21 15:10:34 christos Exp $	*/
 
 /*-
  * Copyright (c) 1998, 1999, 2007, 2009 The NetBSD Foundation, Inc.
@@ -31,7 +31,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_kthread.c,v 1.41 2015/04/21 11:10:29 pooka Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_kthread.c,v 1.42 2017/04/21 15:10:34 christos Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -82,7 +82,7 @@ kthread_create(pri_t pri, int flag, struct cpu_info *ci,
 	}
 
 	error = lwp_create(&lwp0, &proc0, uaddr, LWP_DETACHED, NULL,
-	    0, func, arg, &l, lc);
+	    0, func, arg, &l, lc, &lwp0.l_sigmask, &lwp0.l_sigstk);
 	if (error) {
 		uvm_uarea_system_free(uaddr);
 		return error;
diff --git a/sys/kern/kern_lwp.c b/sys/kern/kern_lwp.c
index 0dfb0c610a88..11a003455122 100644
--- a/sys/kern/kern_lwp.c
+++ b/sys/kern/kern_lwp.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: kern_lwp.c,v 1.187 2017/01/14 19:32:10 kamil Exp $	*/
+/*	$NetBSD: kern_lwp.c,v 1.188 2017/04/21 15:10:34 christos Exp $	*/
 
 /*-
  * Copyright (c) 2001, 2006, 2007, 2008, 2009 The NetBSD Foundation, Inc.
@@ -211,7 +211,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_lwp.c,v 1.187 2017/01/14 19:32:10 kamil Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_lwp.c,v 1.188 2017/04/21 15:10:34 christos Exp $");
 
 #include "opt_ddb.h"
 #include "opt_lockdebug.h"
@@ -760,8 +760,9 @@ lwp_find_free_lid(lwpid_t try_lid, lwp_t * new_lwp, proc_t *p)
  */
 int
 lwp_create(lwp_t *l1, proc_t *p2, vaddr_t uaddr, int flags,
-	   void *stack, size_t stacksize, void (*func)(void *), void *arg,
-	   lwp_t **rnewlwpp, int sclass)
+    void *stack, size_t stacksize, void (*func)(void *), void *arg,
+    lwp_t **rnewlwpp, int sclass, const sigset_t *sigmask,
+    const stack_t *sigstk)
 {
 	struct lwp *l2, *isfree;
 	turnstile_t *ts;
@@ -904,8 +905,8 @@ lwp_create(lwp_t *l1, proc_t *p2, vaddr_t uaddr, int flags,
 	} else
 		l2->l_prflag = 0;
 
-	l2->l_sigstk = l1->l_sigstk;
-	l2->l_sigmask = l1->l_sigmask;
+	l2->l_sigstk = *sigstk;
+	l2->l_sigmask = *sigmask;
 	TAILQ_INIT(&l2->l_sigpend.sp_info);
 	sigemptyset(&l2->l_sigpend.sp_set);
 
diff --git a/sys/kern/kern_sig.c b/sys/kern/kern_sig.c
index 3b2604665e20..03bd794477ca 100644
--- a/sys/kern/kern_sig.c
+++ b/sys/kern/kern_sig.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: kern_sig.c,v 1.335 2017/03/31 08:47:04 martin Exp $	*/
+/*	$NetBSD: kern_sig.c,v 1.336 2017/04/21 15:10:35 christos Exp $	*/
 
 /*-
  * Copyright (c) 2006, 2007, 2008 The NetBSD Foundation, Inc.
@@ -70,7 +70,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: kern_sig.c,v 1.335 2017/03/31 08:47:04 martin Exp $");
+__KERNEL_RCSID(0, "$NetBSD: kern_sig.c,v 1.336 2017/04/21 15:10:35 christos Exp $");
 
 #include "opt_ptrace.h"
 #include "opt_dtrace.h"
@@ -347,9 +347,7 @@ siginit(struct proc *p)
 	 */
 	l = LIST_FIRST(&p->p_lwps);
 	l->l_sigwaited = NULL;
-	l->l_sigstk.ss_flags = SS_DISABLE;
-	l->l_sigstk.ss_size = 0;
-	l->l_sigstk.ss_sp = 0;
+	l->l_sigstk = SS_INIT;
 	ksiginfo_queue_init(&l->l_sigpend.sp_info);
 	sigemptyset(&l->l_sigpend.sp_set);
 
@@ -417,9 +415,7 @@ execsigs(struct proc *p)
 	 */
 	l = LIST_FIRST(&p->p_lwps);
 	l->l_sigwaited = NULL;
-	l->l_sigstk.ss_flags = SS_DISABLE;
-	l->l_sigstk.ss_size = 0;
-	l->l_sigstk.ss_sp = 0;
+	l->l_sigstk = SS_INIT;
 	ksiginfo_queue_init(&l->l_sigpend.sp_info);
 	sigemptyset(&l->l_sigpend.sp_set);
 	mutex_exit(p->p_lock);
diff --git a/sys/kern/sys_aio.c b/sys/kern/sys_aio.c
index f36f9bd59c51..611bd1f1bf83 100644
--- a/sys/kern/sys_aio.c
+++ b/sys/kern/sys_aio.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: sys_aio.c,v 1.41 2016/07/07 06:55:43 msaitoh Exp $	*/
+/*	$NetBSD: sys_aio.c,v 1.42 2017/04/21 15:10:35 christos Exp $	*/
 
 /*
  * Copyright (c) 2007 Mindaugas Rasiukevicius <rmind at NetBSD org>
@@ -32,7 +32,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: sys_aio.c,v 1.41 2016/07/07 06:55:43 msaitoh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: sys_aio.c,v 1.42 2017/04/21 15:10:35 christos Exp $");
 
 #ifdef _KERNEL_OPT
 #include "opt_ddb.h"
@@ -211,7 +211,7 @@ aio_procinit(struct proc *p)
 		return EAGAIN;
 	}
 	error = lwp_create(curlwp, p, uaddr, 0, NULL, 0, aio_worker,
-	    NULL, &l, curlwp->l_class);
+	    NULL, &l, curlwp->l_class, &curlwp->l_sigmask, &curlwp->l_sigstk);
 	if (error != 0) {
 		uvm_uarea_free(uaddr);
 		aio_exit(p, aio);
diff --git a/sys/kern/sys_lwp.c b/sys/kern/sys_lwp.c
index 5821859fe536..b102a588da72 100644
--- a/sys/kern/sys_lwp.c
+++ b/sys/kern/sys_lwp.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: sys_lwp.c,v 1.58 2017/01/15 01:28:14 maya Exp $	*/
+/*	$NetBSD: sys_lwp.c,v 1.59 2017/04/21 15:10:35 christos Exp $	*/
 
 /*-
  * Copyright (c) 2001, 2006, 2007, 2008 The NetBSD Foundation, Inc.
@@ -35,7 +35,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: sys_lwp.c,v 1.58 2017/01/15 01:28:14 maya Exp $");
+__KERNEL_RCSID(0, "$NetBSD: sys_lwp.c,v 1.59 2017/04/21 15:10:35 christos Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -70,7 +70,8 @@ lwp_sys_init(void)
 }
 
 int
-do_lwp_create(lwp_t *l, void *arg, u_long flags, lwpid_t *new_lwp)
+do_lwp_create(lwp_t *l, void *arg, u_long flags, lwpid_t *new_lwp,
+    const sigset_t *sigmask, const stack_t *sigstk)
 {
 	struct proc *p = l->l_proc;
 	struct lwp *l2;
@@ -84,8 +85,8 @@ do_lwp_create(lwp_t *l, void *arg, u_long flags, lwpid_t *new_lwp)
 	if (__predict_false(uaddr == 0))
 		return ENOMEM;
 
-	error = lwp_create(l, p, uaddr, flags & LWP_DETACHED,
-	    NULL, 0, p->p_emul->e_startlwp, arg, &l2, l->l_class);
+	error = lwp_create(l, p, uaddr, flags & LWP_DETACHED, NULL, 0,
+	    p->p_emul->e_startlwp, arg, &l2, l->l_class, sigmask);
 	if (__predict_false(error)) {
 		uvm_uarea_free(uaddr);
 		return error;
@@ -152,7 +153,10 @@ sys__lwp_create(struct lwp *l, const struct sys__lwp_create_args *uap,
 	if (error)
 		goto fail;
 
-	error = do_lwp_create(l, newuc, SCARG(uap, flags), &lid);
+	const sigset_t *sigmask = newuc->uc_flags & _UC_SIGMASK ?
+	    &newuc->uc_sigmask : &l->l_sigmask;
+	error = do_lwp_create(l, newuc, SCARG(uap, flags), &lid, sigmask,
+	    &SS_INIT);
 	if (error)
 		goto fail;
 
diff --git a/sys/rump/librump/rumpkern/threads.c b/sys/rump/librump/rumpkern/threads.c
index 2e9ffa6baba1..3119e52fe6d3 100644
--- a/sys/rump/librump/rumpkern/threads.c
+++ b/sys/rump/librump/rumpkern/threads.c
@@ -1,4 +1,4 @@
-/*	$NetBSD: threads.c,v 1.24 2016/01/26 23:12:18 pooka Exp $	*/
+/*	$NetBSD: threads.c,v 1.25 2017/04/21 15:10:35 christos Exp $	*/
 
 /*
  * Copyright (c) 2007-2009 Antti Kantee.  All Rights Reserved.
@@ -29,7 +29,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: threads.c,v 1.24 2016/01/26 23:12:18 pooka Exp $");
+__KERNEL_RCSID(0, "$NetBSD: threads.c,v 1.25 2017/04/21 15:10:35 christos Exp $");
 
 #include <sys/param.h>
 #include <sys/atomic.h>
@@ -293,8 +293,9 @@ lwpbouncer(void *arg)
 
 int
 lwp_create(struct lwp *l1, struct proc *p2, vaddr_t uaddr, int flags,
-           void *stack, size_t stacksize, void (*func)(void *), void *arg,
-           struct lwp **newlwpp, int sclass)
+    void *stack, size_t stacksize, void (*func)(void *), void *arg,
+    struct lwp **newlwpp, int sclass, const sigmask_t *sigmask,
+    const stack_t *sigstk)
 {
 	struct thrdesc *td;
 	struct lwp *l;
diff --git a/sys/sys/lwp.h b/sys/sys/lwp.h
index 0c578c5c1289..7ed5fa20bf18 100644
--- a/sys/sys/lwp.h
+++ b/sys/sys/lwp.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: lwp.h,v 1.173 2017/04/08 00:25:50 kamil Exp $	*/
+/*	$NetBSD: lwp.h,v 1.174 2017/04/21 15:10:35 christos Exp $	*/
 
 /*-
  * Copyright (c) 2001, 2006, 2007, 2008, 2009, 2010
@@ -341,7 +341,8 @@ void	lwp_need_userret(lwp_t *);
 void	lwp_free(lwp_t *, bool, bool);
 uint64_t lwp_pctr(void);
 int	lwp_setprivate(lwp_t *, void *);
-int	do_lwp_create(lwp_t *, void *, u_long, lwpid_t *);
+int	do_lwp_create(lwp_t *, void *, u_long, lwpid_t *, const sigset_t *,
+    const stack_t *);
 
 void	lwpinit_specificdata(void);
 int	lwp_specific_key_create(specificdata_key_t *, specificdata_dtor_t);
@@ -422,8 +423,8 @@ lwp_eprio(lwp_t *l)
 	return MAX(l->l_auxprio, pri);
 }
 
-int lwp_create(lwp_t *, struct proc *, vaddr_t, int,
-    void *, size_t, void (*)(void *), void *, lwp_t **, int);
+int lwp_create(lwp_t *, struct proc *, vaddr_t, int, void *, size_t,
+    void (*)(void *), void *, lwp_t **, int, const sigset_t *, const stack_t *);
 
 /*
  * XXX _MODULE
diff --git a/sys/sys/signal.h b/sys/sys/signal.h
index 3217cf38dfff..96e5eed1a4f1 100644
--- a/sys/sys/signal.h
+++ b/sys/sys/signal.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: signal.h,v 1.71 2016/08/04 06:43:43 christos Exp $	*/
+/*	$NetBSD: signal.h,v 1.72 2017/04/21 15:10:35 christos Exp $	*/
 
 /*
  * Copyright (c) 1982, 1986, 1989, 1991, 1993
@@ -170,6 +170,10 @@ struct	sigaction {
 
 #if defined(_NETBSD_SOURCE)
 typedef	void (*sig_t)(int);	/* type of signal function */
+
+#define SS_INIT 		/* Initializer for stack_t */ \
+    ((stack_t) { .ss_sp = NULL, .ss_flags = SS_DISABLE,  .ss_size = 0 })
+
 #endif
 
 #if (defined(_XOPEN_SOURCE) && defined(_XOPEN_SOURCE_EXTENDED)) || \