Re: kern/55933: diskless machine hangs at boot

[Martin Husemann <martin%duskware.de@localhost>]

The following reply was made to PR kern/55933; it has been noted by GNATS.

From: Martin Husemann <martin%duskware.de@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: 
Subject: Re: kern/55933: diskless machine hangs at boot
Date: Mon, 18 Jan 2021 14:02:31 +0100

 The effect is very volatile, adding simple debug code to cdbw_open()
 makes the issue go away, but also confirms that *no* use of the cdbw
 code happens before the hang.
 
 Maybe some libc code layout issue and the cdbw change pushing things
 to a new (not yet used before) page? Plus some emac(4) driver bug breaking
 NFS traffic?
 
 In case of the hang the shell executing /etc/rc gets into rc.d/network,
 close to the end and hangs in 
 
 	load_rc_config_var dhcpcd dhcpcd
 
 right after testing the function was called with two args (so maybe
 the following eval failed to exec a new sh?)
 
 With "set -X" added to the start of rc.d/network:
 
 ---8<---
 Setting sysctl variables:
 ddb.onpanic: 1 -> 0
 + name=network
 + start_cmd=network_start
 + stop_cmd=network_stop
 + nl='
 '
 + load_rc_config network
 + _command=network
 + '[' -z network ']'
 + true
 + ':'
 + '[' -f /etc/rc.conf.d/network ']'
 + load_rc_config_var dhcpcd dhcpcd
 + '[' 2 -ne 2 ']'
 --->8---
 
 Any ideas how to trace this further?
 
 Martin