kern/38060: blocking TSTP is broken

[yamt%mwd.biglobe.ne.jp@localhost]

>Number:         38060
>Category:       kern
>Synopsis:       blocking TSTP is broken
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Feb 19 03:05:00 +0000 2008
>Originator:     YAMAMOTO Takashi <yamt%mwd.biglobe.ne.jp@localhost>
>Release:        see below
>Organization:
        
>Environment:
        NetBSD shiny.astron.com 4.99.54 NetBSD 4.99.54 (SHINY)
        #123: Sun Feb 10 14:58:12 EST 2008
        
christos%shiny.astron.com@localhost:/usr/src/sys/arch/i386/compile/SHINY i386
>Description:
        according to christos@, blocking SIGTSTP is broken.

        <crispytoast> here's the test program for sigblock
        <crispytoast> This is what breaks emacs, less, mail, etc.@ said

#include <stdio.h>
#include <unistd.h>
#include <signal.h>
main()
{
        sigset_t set;
        sigemptyset(&set);
        sigaddset(&set, SIGTSTP);
        sigprocmask(SIG_BLOCK, &set, NULL);
        for (;;) {
                printf("killing\n");
                kill(-getpgrp(), SIGTSTP);
                printf("back\n");
        }
}

>How-To-Repeat:
>Fix: