This is an intermittent bug, but this is what syslog shows when the system gets in this state: Jun 13 15:35:02 sc143 telnetd[4381]: can't open '/dev/ttyp0': Input/output error Jun 13 15:36:24 sc143 telnetd[4585]: can't open '/dev/ttyp0': Input/output error Jun 13 15:36:40 sc143 telnetd[4631]: can't open '/dev/ttyp0': Input/output error root@sc143:/etc/init.d# which telnetd /usr/sbin/telnetd root@sc143:/etc/init.d# ls -la /usr/sbin/telnetd lrwxrwxrwx 1 root root 17 2012-06-08 14:43 /usr/sbin/telnetd -> ../../bin/busybox root@sc143:/etc/init.d# busybox BusyBox v1.19.4 (2012-03-01 11:02:04 CST) multi-call binary. Copyright (C) 1998-2011 Erik Andersen, Rob Landley, Denys Vlasenko and others. Licensed under GPLv2. See source distribution for full notice. Usage: busybox [function] [arguments]... or: busybox --list[-full] or: function [arguments]... BusyBox is a multi-call binary that combines many common Unix utilities into a single executable. Most people will create a link to busybox for each function they wish to use and BusyBox will act like whatever it was invoked as. Currently defined functions: adjtimex, clear, cmp, dos2unix, eject, free, iostat, mesg, mktemp, mpstat, nc, nmeter, nslookup, pipe_progress, reset, run-parts, setconsole, start-stop-daemon, stat, strings, telnetd, time, traceroute, unix2dos, uudecode, uuencode, which This is how busybox is configured. # grep -i telnetd config CONFIG_TELNETD=y CONFIG_FEATURE_TELNETD_STANDALONE=y # CONFIG_FEATURE_TELNETD_INETD_WAIT is not set telnetd is started from /etc/init.d like so: /usr/sbin/telnetd -l /bin/login Any ideas what could be the root cause of this? Googling turns up lots noise but nothing that looks like this issue.
Do you have FEATURE_DEVPTS enabled? Does bug go away if you flip it and rebuild? config FEATURE_DEVPTS bool "Use the devpts filesystem for Unix98 PTYs" default y help Enable if you want BusyBox to use Unix98 PTY support. If enabled, busybox will use /dev/ptmx for the master side of the pseudoterminal and /dev/pts/<number> for the slave side. Otherwise, BSD style /dev/ttyp<number> will be used. To use this option, you should have devpts mounted.
(In reply to comment #1) > Do you have FEATURE_DEVPTS enabled? > > Does bug go away if you flip it and rebuild? > > > config FEATURE_DEVPTS > bool "Use the devpts filesystem for Unix98 PTYs" > default y > help > Enable if you want BusyBox to use Unix98 PTY support. If enabled, > busybox will use /dev/ptmx for the master side of the pseudoterminal > and /dev/pts/<number> for the slave side. Otherwise, BSD style > /dev/ttyp<number> will be used. To use this option, you should have > devpts mounted. I did have devpts mounted on /dev/pts type devpts (rw,relatime,gid=5,mode=620), but I did not have this feature enabled. Giving it a try now, thanks.
Seems like it wasn't a bug. Closing.