kern/154676: [netgraph] [panic] HEAD, 8.1-RELEASE panic after some play with netgraph

[Arnaud Lacombe]

The following reply was made to PR kern/154676; it has been noted by GNATS.

From: Arnaud Lacombe <lacombar at gmail.com>
To: bug-followup at FreeBSD.org, sergey.dyatko at gmail.com
Cc:  
Subject: Re: kern/154676: [netgraph] [panic] HEAD, 8.1-RELEASE panic after
 some play with netgraph
Date: Sun, 13 Feb 2011 02:03:34 -0500

 Playing a bit with that bug; an INVARIANTS-enabled kernel (9-CURRENT)
 crashes with:
 
 panic: ng_snd_item: no mbuf packet header!
 
 because the mbuf returned by soreceive() does not have M_PKTHDR set,
 while the expected data is present in the mbuf. 7.1 does set the flag:
 
 Adding an m_print() right after soreceive() in ng_ksocket_incoming2() gives:
 
 FreeBSD -current (on 127.0.0.1:25):
 mbuf: 0xc1d7b200 len: 81, next: 0, 0, 32-32-30-...
 
 FreeBSD 7.1 (on 127.0.0.1:22)
 mbuf: 0xc6d47400 len: 40, next: 0, 2<pkthdr>, 53-53-48-...
 
 both stack uses soreceive_generic(),