From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <140e7ec30802150120y1b0e4b33lf76787aaee84edd2@mail.gmail.com>
Date: Fri, 15 Feb 2008 18:20:13 +0900
From: sqweek <sqweek@gmail.com>
To: 9fans@cse.psu.edu
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Subject: [9fans] /net panic
Topicbox-Message-UUID: 548108dc-ead3-11e9-9d60-3106f5b1d025

 muzgo (from irc) was playing around with /net in qemu and came across this gem:

on drawterm:
cpu% cd /net/tcp
cpu% cat clone
23cpu% cd 23
cpu% echo connect 10.0.2.1!12345 >ctl
cpu% cat status
Finwait2 qin 0 qout 0 srtt 0 mdev 0 cwin 1461 swin 32850>>0 rwin
65535>>0 timer.start 10 timer.count 10 rerecv 0 katimer.start 200
katimer.count 159
cpu% echo connect 10.0.2.1!12345 >ctl
cpu%

this causes CPU server to reboot with:
panic: timerstate1
panic: timerstate1
dumpstack disabled
cpu0 exiting


 The usage of /net is invalid, but you wouldn't really expect that to
reboot the machine (or maybe it's a holdover from before /dev/reboot
existed? ;) ).
 Just tried it on my cpu server and got the same panic, so we can rule
qemu out. I adjusted the ip!port to something that would accept my
connection, and my status was something like Timedwait rather than
Finwait2. Second time around I skipped the cat status and still hit
the panic so the status read isn't affecting things (which is probably
blindingly obvious to anyone familiar with the /net code, but oh
well).

 I appear to be running a realtek 8169 nic:
#l0: rtl8169: 100Mbps port 0xE400 irq 11: 000aeb2ff32c

 Don't know what muzgo was using in qemu, but let me know if I can
provide any useful information.
-sqweek