kern/73321: Reproducible Panic (LOR: I4B / INET6)

[StefanEßer]

The following reply was made to PR kern/73321; it has been noted by GNATS.

From: Stefan =?iso-8859-1?Q?E=DFer?= <se at FreeBSD.org>
To: freebsd-gnats-submit at FreeBSD.org
Cc:  
Subject: Re: kern/73321: Reproducible Panic (LOR: I4B / INET6)
Date: Mon, 1 Nov 2004 23:50:02 +0100

 I have identifed the cause of the panic. It seems, that it is caused
 by NETGRAPH calling net_add_domain() during SYSINIT(SI_SUB_PSEUDO)
 to add the netgraph address family and protocol. That function must
 not be called before phase SI_SUB_PROTO_DOMAIN, though, or incomplete
 initialization of network device structures will result, leading to
 a panic during INET6 neighbour discovery.
 
 The following work-around moves the initialization of all i4b devices
 before netgraph, as required:
 
 Index: i4b/include/i4b_global.h
 --- i4b/include/i4b_global.h	15 Jul 2004 08:26:05 -0000	1.12
 +++ i4b/include/i4b_global.h	1 Nov 2004 18:48:07 -0000
 @@ -67,7 +67,8 @@
  		name ## _modevent, \
  		(void *)sym \
  	}; \
 -	DECLARE_MODULE(name, name ## _mod, SI_SUB_PSEUDO, SI_ORDER_ANY)
 +	/* XXX work-around: i4b must be initialized before netgraph! */ \
 +	DECLARE_MODULE(name, name ## _mod, SI_SUB_PSEUDO, SI_ORDER_MIDDLE)
  #endif
  
  /*---------------*/
 
 This is only a work-around, since netgraph should really not call
 net_add_domain() before phase SI_SUB_PROTO_DOMAIN!