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Date:      Sun, 18 Jul 2004 13:23:14 GMT
From:      David Xu <davidxu@FreeBSD.org>
To:        Perforce Change Reviews <perforce@freebsd.org>
Subject:   PERFORCE change 57626 for review
Message-ID:  <200407181323.i6IDNEea089969@repoman.freebsd.org>
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http://perforce.freebsd.org/chv.cgi?CH=57626

Change 57626 by davidxu@davidxu_alona on 2004/07/18 13:22:44

	Refine code ptracestop.
	Don't schdule upcall in trapsignal if the signal is a debug
	signal and we are being debugged, this allows debugger to resume
	and single step the thread without going into UTS which maybe be
	blocked by schedule lock or other blockable objects.

Affected files ...

.. //depot/projects/davidxu_ksedbg/src/sys/kern/kern_sig.c#12 edit

Differences ...

==== //depot/projects/davidxu_ksedbg/src/sys/kern/kern_sig.c#12 (text+ko) ====

@@ -1484,24 +1484,13 @@
 
 	p = td->td_proc;
 	if (td->td_pflags & TDP_SA) {
-		if (td->td_mailbox == NULL)
-			thread_user_enter(p, td);
-	    	if ((p->p_flag & P_TRACED) && (sig == SIGTRAP)) {
-			mtx_lock_spin(&sched_lock);
-			td->td_flags &= ~TDF_CAN_UNBIND;
-			mtx_unlock_spin(&sched_lock);
+		/* Don't upcall if it is debug signal */
+		if (!((p->p_flag & P_TRACED) && (sig == SIGTRAP))) {
+			if (td->td_mailbox == NULL)
+				thread_user_enter(p, td);
 		}
 		PROC_LOCK(p);
 		SIGDELSET(td->td_sigmask, sig);
-		mtx_lock_spin(&sched_lock);
-		/*
-		 * Force scheduling an upcall, so UTS has chance to
-		 * process the signal before thread runs again in
-		 * userland.
-		 */
-		if (td->td_upcall)
-			td->td_upcall->ku_flags |= KUF_DOUPCALL;
-		mtx_unlock_spin(&sched_lock);
 	} else {
 		PROC_LOCK(p);
 	}
@@ -2016,13 +2005,8 @@
 	td->td_flags |= TDF_XSIG;
 	mtx_unlock_spin(&sched_lock);
 	td->td_xsig = sig;
-	while ((p->p_flag & P_TRACED) && (td->td_flags & TDF_XSIG)) {
-		if (p->p_flag & P_SINGLE_EXIT) {
-			mtx_lock_spin(&sched_lock);
-			td->td_flags &= ~TDF_XSIG;
-			mtx_unlock_spin(&sched_lock);
-			return (sig);
-		}
+	while (!(p->p_flag & P_SINGLE_EXIT) && (p->p_flag & P_TRACED)
+	       && (td->td_flags & TDF_XSIG)) {
 		/*
 		 * Just make wait() to work, the last stopped thread
 		 * will win.
@@ -2049,15 +2033,18 @@
 		mtx_unlock_spin(&sched_lock);
 		PICKUP_GIANT();
 		PROC_LOCK(p);
-		if (!(p->p_flag & P_TRACED))
+		if ((p->p_flag & P_SINGLE_EXIT) || !(p->p_flag & P_TRACED))
 			break;
 		if (td->td_flags & TDF_DBSUSPEND) {
-			if (p->p_flag & P_SINGLE_EXIT)
-				break;
 			mtx_lock_spin(&sched_lock);
 			goto stopme;
 		}
 	}
+	if (td->td_flags & TDF_XSIG) {
+		mtx_lock_spin(&sched_lock);
+		td->td_flags &= ~TDF_XSIG;
+		mtx_unlock_spin(&sched_lock);
+	}
 	return (td->td_xsig);
 }
 
@@ -2111,8 +2098,10 @@
 		 */
 		if (SIGISMEMBER(ps->ps_sigignore, sig) && (traced == 0)) {
 			SIGDELSET(td->td_siglist, sig);
-			if (td->td_pflags & TDP_SA)
+			if (td->td_pflags & TDP_SA) {
 				SIGADDSET(td->td_sigmask, sig);
+				SIG_CANTMASK(td->td_sigmask);
+			}
 			continue;
 		}
 		if (p->p_flag & P_TRACED && (p->p_flag & P_PPWAIT) == 0) {
@@ -2129,8 +2118,10 @@
 			 * otherwise we just look for signals again.
 			 */
 			SIGDELSET(td->td_siglist, sig);	/* clear old signal */
-			if (td->td_pflags & TDP_SA)
+			if (td->td_pflags & TDP_SA) {
 				SIGADDSET(td->td_sigmask, sig);
+				SIG_CANTMASK(td->td_sigmask);
+			}
 			if (newsig == 0)
 				continue;
 			sig = newsig;
@@ -2281,8 +2272,8 @@
 		n++;
 	if ((p->p_flag & P_STOPPED_SIG) && (n == p->p_numthreads)) {
 		mtx_unlock_spin(&sched_lock);
+		PROC_LOCK(p->p_pptr);
 		stop(p);
-		PROC_LOCK(p->p_pptr);
 		ps = p->p_pptr->p_sigacts;
 		mtx_lock(&ps->ps_mtx);
 		if ((ps->ps_flag & PS_NOCLDSTOP) == 0) {

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