port-amd64/55661: pppoe renegotiation timeout causing panic

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>Number:         55661
>Category:       port-amd64
>Synopsis:       pppoe renegotiation timeout causing panic
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    port-amd64-maintainer
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Tue Sep 15 07:10:00 +0000 2020
>Originator:     Ben Gergely
>Release:        9.99.72
>Organization:
>Environment:
NetBSD 9.99.72 amd64
>Description:
Kinda hard to debug because it requires my ISP to fall on it's face.

I didnt manage to grab the other panic that mentioned an xcall which didnt get tee'd to the log.

I'm assuming the panics are from trying to renegotiate a pppoe session after a PADI timeout, I've not got a pppd log to check specifically what happened just before but a timeout it's an educated guess based on what what was happening with the ISP.



Sep 15 03:46:27 sludge /usr/sbin/ifwatchd[731]: watching interface pppoe0
Sep 15 03:46:27 sludge npfd: reopening pcap socket
Sep 15 03:46:27 sludge npfd: 167 packets read from `/var/log/npflog0.pcap'
Sep 15 03:46:27 sludge savecore: reboot after panic: [   7.6760811] panic: kernel diagnostic assertion "(l->l_pflag & LP_INTR) == 0 || panicstr != NULL" failed: file "/usr/src/sys/kern/kern_condvar.c", line 126 
Sep 15 03:46:27 sludge savecore: system went down at Tue Sep 15 03:45:45 2020

Sep 15 04:47:55 sludge /usr/sbin/ifwatchd[731]: watching interface pppoe0
Sep 15 04:47:55 sludge npfd: reopening pcap socket
Sep 15 04:47:55 sludge npfd: 176 packets read from `/var/log/npflog0.pcap'
Sep 15 04:47:55 sludge savecore: reboot after panic: [   9.0854538] panic: kernel diagnostic assertion "(l->l_pflag & LP_INTR) == 0 || panicstr != NULL" failed: file "/usr/src/sys/kern/kern_condvar.c", line 126 
Sep 15 04:47:55 sludge savecore: system went down at Tue Sep 15 04:47:14 2020

Sep 15 05:11:25 sludge savecore: reboot after panic: [   7.6538159] panic: kernel diagnostic assertion "(l->l_pflag & LP_INTR) == 0 || panicstr != NULL" failed: file "/usr/src/sys/kern/kern_condvar.c", line 126 
Sep 15 05:11:25 sludge savecore: system went down at Tue Sep 15 05:10:44 2020

Sep 15 06:24:33 sludge /usr/sbin/ifwatchd[731]: watching interface pppoe0
Sep 15 06:24:33 sludge npfd: reopening pcap socket
Sep 15 06:24:33 sludge npfd: 176 packets read from `/var/log/npflog0.pcap'
Sep 15 06:24:33 sludge savecore: reboot after panic: [   7.8855546] panic: kernel diagnostic assertion "(l->l_pflag & LP_INTR) == 0 || panicstr != NULL" failed: file "/usr/src/sys/kern/kern_condvar.c", line 126 
Sep 15 06:24:33 sludge savecore: system went down at Tue Sep 15 06:23:52 2020

Sep 15 07:01:02 sludge /usr/sbin/ifwatchd[731]: watching interface pppoe0
Sep 15 07:01:02 sludge npfd: reopening pcap socket
Sep 15 07:01:02 sludge npfd: 177 packets read from `/var/log/npflog0.pcap'
Sep 15 07:01:02 sludge savecore: reboot after panic: [   7.2022737] panic: kernel diagnostic assertion "(l->l_pflag & LP_INTR) == 0 || panicstr != NULL" failed: file "/usr/src/sys/kern/kern_condvar.c", line 126 
Sep 15 07:01:02 sludge savecore: system went down at Tue Sep 15 07:00:21 2020

>How-To-Repeat:
Get your ISP's backhaul to fail so pppoe sessions timeout and endlessly try to renegotiate.

Might work on a tunnel, not tried yet.
>Fix: