kern/133289: [vm] [panic] DEBUG_MEMGUARD with vm.memguard.desc="devbuf" panics the kernel

[mdf at FreeBSD.org]

The following reply was made to PR kern/133289; it has been noted by GNATS.

From: mdf at FreeBSD.org
To: bug-followup at FreeBSD.org, 20080101.freebsd.org at ab.ote.we.lv
Cc:  
Subject: Re: kern/133289: [vm] [panic] DEBUG_MEMGUARD with vm.memguard.desc="devbuf"
 panics the kernel
Date: Wed, 1 Sep 2010 10:54:14 -0700

 Based on the stack trace it looks like mgfifo is NULL (the lines are
 off by one, it appears, but that's the only reasonable place to
 dereference 0x8).
 
 This did not repro on a virtual machine for me.  However, there is a
 new memguard implementation in -current now.  I am unable to determine
 conclusively from just the stack whether this is a bug in memguard or
 if memguard found a bug in the use of M_DEVBUF but didn't print an
 error in a friendly format.
 
 Would it be possible to re-try this on the same hardware, but using
 CURRENT?  If not, I hope to backport the memguard changes in a few
 weeks to stable/8 and stable/7.
 
 Thanks,
 matthew