Index: kern/kern_sig.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/kern_sig.c,v
retrieving revision 1.359
diff -u -r1.359 kern_sig.c
--- kern/kern_sig.c	19 Mar 2008 06:19:00 -0000	1.359
+++ kern/kern_sig.c	20 Mar 2008 08:42:20 -0000
@@ -2286,6 +2286,7 @@
 
 	FOREACH_THREAD_IN_PROC(p, td2) {
 		thread_lock(td2);
+		td2->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
 		if ((TD_IS_SLEEPING(td2) || TD_IS_SWAPPED(td2)) &&
 		    (td2->td_flags & TDF_SINTR) &&
 		    !TD_IS_SUSPENDED(td2)) {
Index: kern/kern_thr.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/kern_thr.c,v
retrieving revision 1.65
diff -u -r1.65 kern_thr.c
--- kern/kern_thr.c	19 Mar 2008 06:19:00 -0000	1.65
+++ kern/kern_thr.c	20 Mar 2008 08:42:20 -0000
@@ -235,6 +235,8 @@
 	/* let the scheduler know about these things. */
 	sched_fork_thread(td, newtd);
 	thread_unlock(td);
+	if (P_SHOULDSTOP(p))
+		newtd->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
 	PROC_UNLOCK(p);
 	thread_lock(newtd);
 	if (rtp != NULL) {
Index: kern/kern_thread.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/kern_thread.c,v
retrieving revision 1.272
diff -u -r1.272 kern_thread.c
--- kern/kern_thread.c	20 Mar 2008 03:07:57 -0000	1.272
+++ kern/kern_thread.c	20 Mar 2008 08:42:20 -0000
@@ -549,7 +549,7 @@
 			if (td2 == td)
 				continue;
 			thread_lock(td2);
-			td2->td_flags |= TDF_ASTPENDING;
+			td2->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
 			if (TD_IS_INHIBITED(td2)) {
 				switch (mode) {
 				case SINGLE_EXIT:
@@ -751,6 +751,7 @@
 	p->p_suspcount++;
 	PROC_UNLOCK(p);
 	thread_lock(td);
+	td->td_flags &= ~TDF_NEEDSUSPCHK;
 	TD_SET_SUSPENDED(td);
 	sched_sleep(td, 0);
 	PROC_SUNLOCK(p);
@@ -771,6 +772,7 @@
 	THREAD_LOCK_ASSERT(td, MA_OWNED);
 	KASSERT(!TD_IS_SUSPENDED(td), ("already suspended"));
 	p->p_suspcount++;
+	td->td_flags &= ~TDF_NEEDSUSPCHK;
 	TD_SET_SUSPENDED(td);
 	sched_sleep(td, 0);
 }
Index: kern/subr_sleepqueue.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/subr_sleepqueue.c,v
retrieving revision 1.50
diff -u -r1.50 subr_sleepqueue.c
--- kern/subr_sleepqueue.c	19 Mar 2008 07:35:14 -0000	1.50
+++ kern/subr_sleepqueue.c	20 Mar 2008 08:42:20 -0000
@@ -391,7 +391,7 @@
 	 * directly.
 	 */
 	thread_lock(td);
-	if ((td->td_flags & TDF_NEEDSIGCHK) == 0) {
+	if ((td->td_flags & (TDF_NEEDSIGCHK | TDF_NEEDSUSPCHK)) == 0) {
 		sleepq_switch(wchan, pri);
 		return (0);
 	}
Index: kern/subr_trap.c
===================================================================
RCS file: /home/ncvs/src/sys/kern/subr_trap.c,v
retrieving revision 1.302
diff -u -r1.302 subr_trap.c
--- kern/subr_trap.c	12 Mar 2008 10:11:59 -0000	1.302
+++ kern/subr_trap.c	20 Mar 2008 08:42:21 -0000
@@ -96,11 +96,9 @@
 	thread_unlock(td);
 	PROC_UNLOCK(p);
 #endif
-
 #ifdef KTRACE
 	KTRUSERRET(td);
 #endif
-
 	/*
 	 * If this thread tickled GEOM, we need to wait for the giggling to
 	 * stop before we return to userland
@@ -109,21 +107,9 @@
 		g_waitidle();
 
 	/*
-	 * We need to check to see if we have to exit or wait due to a
-	 * single threading requirement or some other STOP condition.
-	 * Don't bother doing all the work if the stop bits are not set
-	 * at this time.. If we miss it, we miss it.. no big deal.
-	 */
-	if (P_SHOULDSTOP(p)) {
-		PROC_LOCK(p);
-		thread_suspend_check(0);	/* Can suspend or kill */
-		PROC_UNLOCK(p);
-	}
-	/*
 	 * Charge system time if profiling.
 	 */
 	if (p->p_flag & P_PROFIL) {
-
 		addupc_task(td, TRAPF_PC(frame), td->td_pticks * psratio);
 	}
 	/*
@@ -172,9 +158,8 @@
 	 */
 	thread_lock(td);
 	flags = td->td_flags;
-	td->td_flags &= ~(TDF_ASTPENDING | TDF_NEEDSIGCHK |
-	    TDF_NEEDRESCHED | TDF_ALRMPEND | TDF_PROFPEND |
-	    TDF_MACPEND);
+	td->td_flags &= ~(TDF_ASTPENDING | TDF_NEEDSIGCHK | TDF_NEEDSUSPCHK |
+	    TDF_NEEDRESCHED | TDF_ALRMPEND | TDF_PROFPEND | TDF_MACPEND);
 	thread_unlock(td);
 	PCPU_INC(cnt.v_trap);
 
@@ -242,6 +227,15 @@
 		mtx_unlock(&p->p_sigacts->ps_mtx);
 		PROC_UNLOCK(p);
 	}
+	/*
+	 * We need to check to see if we have to exit or wait due to a
+	 * single threading requirement or some other STOP condition.
+	 */
+	if (flags & TDF_NEEDSUSPCHK) {
+		PROC_LOCK(p);
+		thread_suspend_check(0);
+		PROC_UNLOCK(p);
+	}
 
 	userret(td, framep);
 	mtx_assert(&Giant, MA_NOTOWNED);
Index: sys/proc.h
===================================================================
RCS file: /home/ncvs/src/sys/sys/proc.h,v
retrieving revision 1.508
diff -u -r1.508 proc.h
--- sys/proc.h	20 Mar 2008 05:51:15 -0000	1.508
+++ sys/proc.h	20 Mar 2008 08:42:25 -0000
@@ -309,7 +309,7 @@
 #define	TDF_TIMOFAIL	0x00001000 /* Timeout from sleep after we were awake. */
 #define	TDF_UNUSED2000	0x00002000 /* --available-- */
 #define	TDF_UPIBLOCKED	0x00004000 /* Thread blocked on user PI mutex. */
-#define	TDF_UNUSED15	0x00008000 /* --available-- */
+#define	TDF_NEEDSUSPCHK	0x00008000 /* Thread may need to suspend. */
 #define	TDF_NEEDRESCHED	0x00010000 /* Thread needs to yield. */
 #define	TDF_NEEDSIGCHK	0x00020000 /* Thread may need signal delivery. */
 #define	TDF_XSIG	0x00040000 /* Thread is exchanging signal under trace */