--- kern_sig.c.orig	2014-11-19 08:49:16.000000000 -0200
+++ kern_sig.c	2015-03-08 15:03:41.000000000 -0300
@@ -1003,8 +1003,11 @@
 	int error;
 
 	p = td->td_proc;
-	if (!(flags & SIGPROCMASK_PROC_LOCKED))
+	if ((flags & SIGPROCMASK_PROC_LOCKED) != 0)
+		PROC_LOCK_ASSERT(p, MA_OWNED);
+	else
 		PROC_LOCK(p);
+	mtx_assert(&p->p_sigacts->ps_mtx, ((flags & SIGPROCMASK_PS_LOCKED) != 0) ? MA_OWNED : MA_NOTOWNED);
 	if (oset != NULL)
 		*oset = td->td_sigmask;
 
@@ -1891,6 +1894,30 @@
 	}
 }
 
+
+/*
+ * Recalculate the signal mask and reset the signal disposition after
+ * usermode frame for delivery is formed.  Should be called after
+ * mach-specific routine, because sysent->sv_sendsig() needs correct
+ * ps_siginfo and signal mask.
+ */
+static void
+postsig_done(int sig, struct thread *td, struct sigacts *ps)
+{
+	sigset_t mask;
+
+	mtx_assert(&ps->ps_mtx, MA_OWNED);
+	td->td_ru.ru_nsignals++;
+	mask = ps->ps_catchmask[_SIG_IDX(sig)];
+	if (!SIGISMEMBER(ps->ps_signodefer, sig))
+		SIGADDSET(mask, sig);
+	kern_sigprocmask(td, SIG_BLOCK, &mask, NULL,
+	    SIGPROCMASK_PROC_LOCKED | SIGPROCMASK_PS_LOCKED);
+	if (SIGISMEMBER(ps->ps_sigreset, sig))
+		sigdflt(ps, sig);
+}
+
+
 /*
  * Send a signal caused by a trap to the current thread.  If it will be
  * caught immediately, deliver it with correct code.  Otherwise, post it
@@ -1900,7 +1927,6 @@
 trapsignal(struct thread *td, ksiginfo_t *ksi)
 {
 	struct sigacts *ps;
-	sigset_t mask;
 	struct proc *p;
 	int sig;
 	int code;
@@ -1915,7 +1941,6 @@
 	mtx_lock(&ps->ps_mtx);
 	if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(ps->ps_sigcatch, sig) &&
 	    !SIGISMEMBER(td->td_sigmask, sig)) {
-		td->td_ru.ru_nsignals++;
 #ifdef KTRACE
 		if (KTRPOINT(curthread, KTR_PSIG))
 			ktrpsig(sig, ps->ps_sigact[_SIG_IDX(sig)],
@@ -1923,13 +1948,7 @@
 #endif
 		(*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)],
 				ksi, &td->td_sigmask);
-		mask = ps->ps_catchmask[_SIG_IDX(sig)];
-		if (!SIGISMEMBER(ps->ps_signodefer, sig))
-			SIGADDSET(mask, sig);
-		kern_sigprocmask(td, SIG_BLOCK, &mask, NULL,
-		    SIGPROCMASK_PROC_LOCKED | SIGPROCMASK_PS_LOCKED);
-		if (SIGISMEMBER(ps->ps_sigreset, sig))
-			sigdflt(ps, sig);
+		postsig_done(sig, td, ps);
 		mtx_unlock(&ps->ps_mtx);
 	} else {
 		/*
@@ -2503,9 +2522,10 @@
 	int sig;
 
 	PROC_LOCK_ASSERT(p, MA_OWNED);
+	ps = p->p_sigacts;
+	mtx_assert(&ps->ps_mtx, ((flags & SIGPROCMASK_PS_LOCKED) != 0) ? MA_OWNED : MA_NOTOWNED);
 	if (SIGISEMPTY(p->p_siglist))
 		return;
-	ps = p->p_sigacts;
 	SIGSETAND(block, p->p_siglist);
 	while ((sig = sig_ffs(&block)) != 0) {
 		SIGDELSET(block, sig);
@@ -2811,7 +2831,7 @@
 	struct sigacts *ps;
 	sig_t action;
 	ksiginfo_t ksi;
-	sigset_t returnmask, mask;
+	sigset_t returnmask;
 
 	KASSERT(sig != 0, ("postsig"));
 
@@ -2866,20 +2886,12 @@
 		} else
 			returnmask = td->td_sigmask;
 
-		mask = ps->ps_catchmask[_SIG_IDX(sig)];
-		if (!SIGISMEMBER(ps->ps_signodefer, sig))
-			SIGADDSET(mask, sig);
-		kern_sigprocmask(td, SIG_BLOCK, &mask, NULL,
-		    SIGPROCMASK_PROC_LOCKED | SIGPROCMASK_PS_LOCKED);
-
-		if (SIGISMEMBER(ps->ps_sigreset, sig))
-			sigdflt(ps, sig);
-		td->td_ru.ru_nsignals++;
 		if (p->p_sig == sig) {
 			p->p_code = 0;
 			p->p_sig = 0;
 		}
 		(*p->p_sysent->sv_sendsig)(action, &ksi, &returnmask);
+		postsig_done(sig, td, ps);
 	}
 	return (1);
 }