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Date: Mon,  6 May 2002 14:29:31 +0200 (CEST)
From: Martin Nilsson <martin@gneto.com>
Reply-To: Martin Nilsson <martin@gneto.com>
To: FreeBSD-gnats-submit@freebsd.org
Cc:
Subject: em driver and jumboframes gives instant reboot
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>Number:         37788
>Category:       kern
>Synopsis:       em driver and jumboframes gives instant reboot
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    pdeuskar
>State:          closed
>Quarter:        
>Keywords:       
>Date-Required:  
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Mon May 06 05:30:01 PDT 2002
>Closed-Date:    Fri May 24 07:32:57 PDT 2002
>Last-Modified:  Fri May 24 07:32:57 PDT 2002
>Originator:     Martin Nilsson
>Release:        FreeBSD 4.6-PRERELEASE i386
>Organization:
>Environment:
System: FreeBSD platon.gneto.com 4.6-PRERELEASE FreeBSD 4.6-PRERELEASE #2: Sun May 5 10:44:53 CEST 2002 root@platon.gneto.com:/raid/FreeBSD/obj-RELENG4/raid/FreeBSD/RELENG_4/sys/PLATON i386


	
>Description:
Enable mtu larger than 1500 on an em GigEthernet card and the machine 
reboots when receiving the first jumbo frame
	
>How-To-Repeat:
connect two boxen with intel PRO/1000 XT (82544-based) cards and use the em 
driver set mtu to 9011. Use an NFS mount and do something after a (short) 
while one of the machines will reboot. Set mtu to 1500 and it works!

Using win2000 on one end and Samba on the other doesn't trigger the bug as 
SMB either works over TCP or sends smaller packets.

	
>Fix:
Don't use jumbo frames for now.
	


>Release-Note:
>Audit-Trail:
Responsible-Changed-From-To: freebsd-bugs->pdeuskar 
Responsible-Changed-By: dwmalone 
Responsible-Changed-When: Mon May 6 11:26:49 PDT 2002 
Responsible-Changed-Why:  
The em driver belongs to Prafulla. 

http://www.freebsd.org/cgi/query-pr.cgi?pr=37788 
State-Changed-From-To: open->closed 
State-Changed-By: pdeuskar 
State-Changed-When: Fri May 24 07:30:34 PDT 2002 
State-Changed-Why:  
Haven't received any feedback from the submitter of 
the pr. Also haven't been able to reproduce the 
problem mentioned in the pr. 

-Prafulla 



http://www.freebsd.org/cgi/query-pr.cgi?pr=37788 
>Unformatted:
 I have not been able to reproduce this problem
 with the em driver and 4.6-PRERELEASE with
 jumbo frames.
 
 I would like to see a stack trace of the panic.
 
 -Prafulla
 
 
Haven't received any feedback from the 
submitter of the pr. Also haven't been able to
reproduce the problem.

-Prafulla
 
