i386/87208: /dev/cuad[0/1] bad file descriptor error during mgetty read

[Norbert P. Copones]

>Number:         87208
>Category:       i386
>Synopsis:       /dev/cuad[0/1] bad file descriptor error during mgetty read
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    freebsd-i386
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon Oct 10 13:10:14 GMT 2005
>Closed-Date:
>Last-Modified:
>Originator:     Norbert P. Copones
>Release:        FreeBSD 6.0-RC1
>Organization:
FEU-NRMF
>Environment:
FreeBSD proxy.feu-nrmf.ph 6.0-RC1 FreeBSD 6.0-RC1 #0: Mon Oct 10 17:38:35 PHT 2005     norbert at feu-nrmf.ph:/usr/src/sys/i386/compile/GENERIC   i386
>Description:
The device /dev/cuad[0/1] cannot be accessed by mgetty during startup (mgetty entry in /etc/tty). mgetty log shows this output:

10/10 18:32:46 ad1  mgetty: interim release 1.1.33-Apr10
10/10 18:32:46 ad1  check for lockfiles
10/10 18:32:46 ad1  locking the line
10/10 18:32:47 ad1  mod: cannot make /dev/cuad1 stdin: Bad file descriptor
10/10 18:32:47 ad1  open device /dev/cuad1 failed: Bad file descriptor
10/10 18:32:47 ad1  cannot get terminal line dev=cuad1, exiting: Bad file descriptor
>How-To-Repeat:
setting "cuad1 "/usr/local/sbin/mgetty" unknown  on insecure" in /etc/ttys and rebooting the system.     
>Fix:
i tried changing cuad1 to ttyd1 in /etc/ttys entry and sending HUP signal to init. first attempt always fails (the usual bad file descriptor error), second attempt sometimes succeeds. then switching back ttyd1 to cuad1 again in /etc/ttys and sending HUP signal will error (cuad1: Device busy). so i killed mgetty and again send HUP signal to init and it will succeed at this time.
>Release-Note:
>Audit-Trail:
>Unformatted: