Hi all, Sometimes following error occurs in an UML when enabling the ethernet device:
uml:~ # ifconfig eth0 up SIOCSIFFLAGS: Device or resource busy This happens when logging in to the uml via a telnet port. The problem is that in this case the /dev/net/tun device remains attached to 3 proceses on the host: host:~ # lsof /dev/net/tun COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME in.telnet 7971 hillenr 24u CHR 10,200 4874 /dev/net/tun port-help 7972 hillenr 24u CHR 10,200 4874 /dev/net/tun linux 7974 hillenr 24u CHR 10,200 4874 /dev/net/tun When exiting the telnet session, these 3 processes are terminated and "ifconfig eth0 up" on the uml works again. Following is the complete scenario on how this problem can be reproduced: - After start of an uml instance, a number of processes are attached to the /dev/net/tun device on the host: host:~ # lsof /dev/net/tun COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME linux 7621 hillenr 27u CHR 10,200 4874 /dev/net/tun linux 7627 hillenr 27u CHR 10,200 4874 /dev/net/tun linux 7628 hillenr 27u CHR 10,200 4874 /dev/net/tun linux 7629 hillenr 27u CHR 10,200 4874 /dev/net/tun linux 7630 hillenr 27u CHR 10,200 4874 /dev/net/tun - Now telnet to the uml port and log on. 3 additional processes are created on the host, each attached to /dev/net/tun: host:~ # lsof /dev/net/tun COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME linux 7621 hillenr 27u CHR 10,200 4874 /dev/net/tun linux 7627 hillenr 27u CHR 10,200 4874 /dev/net/tun linux 7628 hillenr 27u CHR 10,200 4874 /dev/net/tun linux 7629 hillenr 27u CHR 10,200 4874 /dev/net/tun linux 7630 hillenr 27u CHR 10,200 4874 /dev/net/tun in.telnet 8496 hillenr 27u CHR 10,200 4874 /dev/net/tun port-help 8497 hillenr 27u CHR 10,200 4874 /dev/net/tun linux 8499 hillenr 27u CHR 10,200 4874 /dev/net/tun - On the uml, take down eth0 with "ifconfig eth0 down". All uml processes are now detached from /dev/net/tun, except the ones related to the telnet session: host:~ # lsof /dev/net/tun COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME in.telnet 8496 hillenr 27u CHR 10,200 4874 /dev/net/tun port-help 8497 hillenr 27u CHR 10,200 4874 /dev/net/tun linux 8499 hillenr 27u CHR 10,200 4874 /dev/net/tun Now as long as the telnet session remains open, the status of eth0 can not be manipulated anymore because of "device or recource busy". I'm not sure if this is a bug on how the /dev/net/tun device is attached to the various uml processes or if this is expected behaviour somehow. Any ideas? Thanks, Robert ------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Do you grep through log files for problems? Stop! Download the new AJAX search engine that makes searching your log files as easy as surfing the web. DOWNLOAD SPLUNK! http://sel.as-us.falkag.net/sel?cmd=lnk&kid=103432&bid=230486&dat=121642 _______________________________________________ User-mode-linux-user mailing list User-mode-linux-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-user
