>Number:         9709
>Category:       bin
>Synopsis:       Dhclinet busy loops if the interface it is trying to use is removed
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    bin-bug-people (Utility Bug People)
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Mar 29 22:30:00 2000
>Last-Modified:
>Originator:     Tero Kivinen
>Organization:
SSH Communications Security
>Release:        NetBSD-current 2000-03-27
>Environment:
System: NetBSD kaakeli.ssh.fi 1.4W NetBSD 1.4W (KAAKELI) #0: Mon Mar 27 18:29:39 CST 2000 ztk@kaakeli.ssh.fi:/usr/src/sys/arch/i386/compile/KAAKELI i386

>Description:

Dhclient does not notice that the interface it is sending the packets
disappears, instead it starts logging "dhclient: receive_packet failed
on wi0: Input/output error" messages to syslog as fast as possible
(more than 350 messages / second).

>How-To-Repeat:

When using wireless card (wi0) turn the interface down by "ifconfig
wi0 down" and then remove the pcmcia card from the slot. After a while
when the dhclient next tries to send anything to the interface it will
start flooding those error messages to the syslog. 

>Fix:

Quick fix: Kill the dhclient before removing pcmcia cards (or before
it tries to use the nonexisting interface).

>Audit-Trail:
>Unformatted: