On Dec 23,  7:55pm, wiz@NetBSD.org (Thomas Klausner) wrote:
-- Subject: kern/37603: ctrl-z handling problem: processes afterwards also st

| >Number:         37603
| >Category:       kern
| >Synopsis:       ctrl-z handling problem: processes afterwards also stopped
| >Confidential:   no
| >Severity:       serious
| >Priority:       medium
| >Responsible:    kern-bug-people
| >State:          open
| >Class:          sw-bug
| >Submitter-Id:   net
| >Arrival-Date:   Sun Dec 23 19:55:01 +0000 2007
| >Originator:     Thomas Klausner
| >Release:        NetBSD 4.99.42/amd64; also on NetBSD 4.99.44/i386 (gson@gson.org)
| >Organization:
| >Environment:
| System: NetBSD hiro 4.99.42 NetBSD 4.99.42 (HIRO64) #5: Wed Dec 19 09:28:31 CET 2007 wiz@hiro:/usr/obj/src.amd64/sys/arch/amd64/compile/HIRO64 amd64
| Architecture: x86_64
| Machine: amd64
| >Description:
| When I stop an emacs21 process on the console, all processes started
| later in the same shell (while emacs is suspended) also immediately seem
| to get a stop signal.
| 
| >How-To-Repeat:
| E.g. boot single user, shell=/bin/ksh
| export TERM=vt100
| emacs -nw a <ctrl-z>
| man man
| 
| The man process will suspend itself after about half a second -- it's
| not immediate, but very quick.
| Putting it in the foreground again doesn't help -- the behaviour
| repeats (man is suspended again immediately).
| 
| Looks like the stop signal sending is stuck :)

This broke in tty.c 1.200 -> 1.201. The deferred tty signal code seems to be
broken. This makes things better, but there is still a problem with the
suspended process receiving an extra TTOUT.

Index: tty.c
===================================================================
RCS file: /cvsroot/src/sys/kern/tty.c,v
retrieving revision 1.208
diff -u -u -r1.208 tty.c
--- tty.c	8 Dec 2007 19:29:49 -0000	1.208
+++ tty.c	23 Dec 2007 20:41:08 -0000
@@ -843,8 +843,10 @@
 		while (isbackground(curproc, tp) &&
 		    p->p_pgrp->pg_jobc && (p->p_sflag & PS_PPWAIT) == 0 &&
 		    !sigismasked(l, SIGTTOU)) {
+			mutex_enter(&proclist_mutex);
+			pgsignal(p->p_pgrp, SIGTTOU, 1);
+			mutex_exit(&proclist_mutex);
 			mutex_spin_enter(&tty_lock);
-			ttysig(tp, TTYSIG_PG1, SIGTTOU);
 			error = ttysleep(tp, &lbolt, true, 0);
 			mutex_spin_exit(&tty_lock);
 			if (error) {
@@ -1631,7 +1633,9 @@
 			mutex_spin_exit(&tty_lock);
 			return (EIO);
 		}
-		ttysig(tp, TTYSIG_PG1, SIGTTIN);
+		mutex_enter(&proclist_mutex);
+		pgsignal(p->p_pgrp, SIGTTIN, 1);
+		mutex_exit(&proclist_mutex);
 		error = ttysleep(tp, &lbolt, true, 0);
 		mutex_spin_exit(&tty_lock);
 		if (error)
@@ -1896,8 +1900,10 @@
 			error = EIO;
 			goto out;
 		}
+		mutex_enter(&proclist_mutex);
+		pgsignal(p->p_pgrp, SIGTTOU, 1);
+		mutex_exit(&proclist_mutex);
 		mutex_spin_enter(&tty_lock);
-		ttysig(tp, TTYSIG_PG1, SIGTTOU);
 		error = ttysleep(tp, &lbolt, true, 0);
 		mutex_spin_exit(&tty_lock);
 		if (error)