misc/94750: watch utility faults when tty disconnects

[J. Hunt]

>Number:         94750
>Category:       misc
>Synopsis:       watch utility faults when tty disconnects
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon Mar 20 19:50:18 GMT 2006
>Closed-Date:
>Last-Modified:
>Originator:     J. Hunt
>Release:        FreeBSD 6.0-RELEASE
>Organization:
>Environment:
FreeBSD .diconconnections.com 6.0-RELEASE FreeBSD 6.0-RELEASE #0: Thu Nov  3 09:36:13 UTC 2005      root at x64.samsco.home:/usr/obj/usr/src/sys/GENERIC  i386
>Description:
When using the "watch" utility with options "-co" all works fine until the tty session disconnects.  "watch" then proceeds to use 100% of the processor.  If the tty reconnects, "watch" crashes and terminates.  This is not true in FreeBSD 5.4.
>How-To-Repeat:
Use a fresh install of 6.0-RELEASE.  SSH to localhost and connect to a tty, for example, /dev/ttyp0.  From the console (or any other terminal) type "watch -co /dev/ttyp0".  After confirming that watch works, disconnect the ssh session and verify with another tty (perhaps /dev/ttyv1 or any other terminal that is observing and is not ttyp0) that watch begins to use 100% of the CPU (top shows this).  Upon reconnect to the watched tty (in this example /dev/ttyp0), watch will crash.
>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted: