The following reply was made to PR port-i386/36206; it has been noted by GNATS.

From: Andrew Doran <ad@netbsd.org>
To: gnats-bugs@NetBSD.org
Cc: port-i386-maintainer@netbsd.org, gnats-admin@netbsd.org,
	netbsd-bugs@netbsd.org, shannonr@NetBSD.org, drochner@netbsd.org
Subject: Re: port-i386/36206: Segmentation faults with SMP on i386 multiprocessor kernel
Date: Thu, 14 Jun 2007 14:44:03 +0100

 On Thu, Jun 14, 2007 at 01:35:04PM +0000, Greg Oster wrote:
 > The following reply was made to PR port-i386/36206; it has been noted by GNATS.
 > 
 > From: Greg Oster <oster@cs.usask.ca>
 > To: gnats-bugs@NetBSD.org
 > Cc: 
 > Subject: Re: port-i386/36206: Segmentation faults with SMP on i386 multiprocessor kernel 
 > Date: Thu, 14 Jun 2007 07:33:06 -0600
 > 
 >  shannonr@NetBSD.org writes:
 >  > >Number:         36206
 >  > >Category:       port-i386
 >  > >Synopsis:       Apparently random segmentation faults occur frequently with 
 >  > SMP kernel on dual Intel Core 2 system.
 >  > >Confidential:   no
 >  > >Severity:       critical
 >  > >Priority:       high
 >  > >Responsible:    port-i386-maintainer
 >  > >State:          open
 >  > >Class:          sw-bug
 >  > >Submitter-Id:   net
 >  > >Arrival-Date:   Tue Apr 24 16:15:00 +0000 2007
 >  > >Originator:     John R. Shannon
 >  > >Release:        NetBSD 4.99.18 (also occurs with 4.0 BETA)
 >  > >Organization:
 >  > 	johnrshannon.com
 >  > >Environment:
 >  > System: NetBSD michael.internal.johnrshannon.com 4.99.18 NetBSD 4.99.18 (KERN
 >  > EL.MICHAEL) #3: Tue Apr 24 08:20:29 MDT 2007 build@michael.internal.johnrshan
 >  > non.com:/usr/obj/import/CURRENT/src/sys/arch/i386/compile/KERNEL.MICHAEL i386
 >  > 	dual Intel Core 2 (Merom)
 >  > 	dmesg output appended to PR
 >  > Architecture: i386
 >  > Machine: i386
 >  > >Description:
 >  > 	Segmentation faults, in different processes, occur every minute or so.
 >  > 	The same kernel, without options MULTIPROCESSOR, works fine. Also, a 
 >  > 	64-bit kernel does not display this behavior.
 >  
 >  Intel released a microcode patch that apparently fixes some TLB 
 >  issues in certain Core 2 Duo CPUs.  (Look for 
 >  "intel microcode update intel core 2 duo" on google).  Maybe a BIOS 
 >  update (that contains the microcode update) would be sufficient to 
 >  solve this problem?  (My Core 2 Duo box (with the update) runs 
 >  flawlessly in MULTIPROCESSOR mode, albeit in 32-bit mode...)
 
 Good news.
 
 Adding a tlbflushg() in pmap_destroy() is a workaround. Matthias Drochner
 tested this and it's confirmed. The problem seems to be limited to Intel
 Core 2 cpus. Sorry for not noting this in the PR earlier.
 
 Andrew