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Date: Tue, 9 Mar 2004 03:59:05 -0800 (PST)
From: ian j hart <ict@cardinalnewman.coventry.sch.uk>
To: freebsd-gnats-submit@FreeBSD.org
Subject: em0 hardware checksum offloading causes bogus errors in tcpdump
X-Send-Pr-Version: www-2.3

>Number:         63982
>Category:       kern
>Synopsis:       em0 hardware checksum offloading causes bogus errors in tcpdump
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    linimon
>State:          closed
>Quarter:        
>Keywords:       
>Date-Required:  
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Tue Mar 09 04:00:31 PST 2004
>Closed-Date:    Wed Apr 05 00:33:29 GMT 2006
>Last-Modified:  Wed Apr 05 00:33:29 GMT 2006
>Originator:     ian j hart
>Release:        4.9-RELEASEp3
>Organization:
Cardinal Newman School
>Environment:
backup.cardinalnewman.lan 4.9-RELEASE-p3 FreeBSD 4.9-RELEASE-p3 #12: Tue Mar  9 10:13:10 GMT 2004     root@backup.cardinalnewman.lan:/usr/obj/usr/src/sys/GENERIC  i386

patched with src/sys/dev/em from RELENG_4
>Description:
      Running tcpdump -v shows many packets marked as having bad
checksums. The packets are delivered okay with correct checksums. This
mainly affects UDP.

I booted from disc2.iso for 4.7, 4.8, and 5.2.1RC and confirmed the
problem there.

One motherboard (GA-7VAXP-A Ultra) DOES work but all others tried so far, fail. Card in different slots, natch`. irq/timing?

>How-To-Repeat:
      tcpdump -v | grep bad
Then generate some UDP traffic
>Fix:
      A workaround and proof of the source of the problem is to
disable the hardware checksum.

/usr/src/sys/dev/em/if_em.h
#define EM_CHECKSUM_FEATURES            (CSUM_TCP | CSUM_UDP)

Set to zero
>Release-Note:
>Audit-Trail:

From: ian j hart <ict@cardinalnewman.coventry.sch.uk>
To: freebsd-gnats-submit@FreeBSD.org
Cc:  
Subject: kern/63982: em0 hardware checksum offloading causes bogus errors in
	tcpdump
Date: Tue, 9 Mar 2004 03:59:05 -0800 (PST)

 >Number:         63982
 >Category:       kern
 >Synopsis:       em0 hardware checksum offloading causes bogus errors in tcpdump
 >Confidential:   no
 >Severity:       non-critical
 >Priority:       low
 >Responsible:    freebsd-bugs
 >State:          open
 >Quarter:        
 >Keywords:       
 >Date-Required:
 >Class:          sw-bug
 >Submitter-Id:   current-users
 >Arrival-Date:   Tue Mar 09 04:00:31 PST 2004
 >Closed-Date:
 >Last-Modified:
 >Originator:     ian j hart
 >Release:        4.9-RELEASEp3
 >Organization:
 Cardinal Newman School
 >Environment:
 backup.cardinalnewman.lan 4.9-RELEASE-p3 FreeBSD 4.9-RELEASE-p3 #12: Tue Mar  9 10:13:10 GMT 2004     root@backup.cardinalnewman.lan:/usr/obj/usr/src/sys/GENERIC  i386
 
 patched with src/sys/dev/em from RELENG_4
 >Description:
       Running tcpdump -v shows many packets marked as having bad
 checksums. The packets are delivered okay with correct checksums. This
 mainly affects UDP.
 
 I booted from disc2.iso for 4.7, 4.8, and 5.2.1RC and confirmed the
 problem there.
 
 One motherboard (GA-7VAXP-A Ultra) DOES work but all others tried so far, fail. Card in different slots, natch`. irq/timing?
 
 >How-To-Repeat:
       tcpdump -v | grep bad
 Then generate some UDP traffic
 >Fix:
       A workaround and proof of the source of the problem is to
 disable the hardware checksum.
 
 /usr/src/sys/dev/em/if_em.h
 #define EM_CHECKSUM_FEATURES            (CSUM_TCP | CSUM_UDP)
 
 Set to zero
 >Release-Note:
 >Audit-Trail:
 >Unformatted:
 _______________________________________________
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Responsible-Changed-From-To: freebsd-bugs->tackerman 
Responsible-Changed-By: wilko 
Responsible-Changed-When: Mon Jun 7 20:34:49 GMT 2004 
Responsible-Changed-Why:  
Tony takes care of the Intel drivers 


http://www.freebsd.org/cgi/query-pr.cgi?pr=63982 
State-Changed-From-To: open->feedback 
State-Changed-By: bms 
State-Changed-When: Mon Jun 14 14:35:15 GMT 2004 
State-Changed-Why:  
I can't observe this behaviour in 4.10-RELEASE with an em(4) adapter 
(onboard on a Dell machine, the vintage of which I can't remember) 

http://www.freebsd.org/cgi/query-pr.cgi?pr=63982 

From: ian j hart <ianjhart@ntlworld.com>
To: freebsd-gnats-submit@FreeBSD.org,
	ict@cardinalnewman.coventry.sch.uk
Cc:  
Subject: Re: kern/63982: em0 hardware checksum offloading causes bogus errors in tcpdump
Date: Sun, 20 Jun 2004 13:32:41 +0100

 http://docs.freebsd.org/cgi/mid.cgi?200404201901.35819.ianjhart
 
 Anyway, whatever it was, it appears to be fixed.
State-Changed-From-To: feedback->closed 
State-Changed-By: linimon 
State-Changed-When: Wed Apr 5 00:32:53 UTC 2006 
State-Changed-Why:  
Submitter notes that the problem was resolved. 


Responsible-Changed-From-To: tackerman->linimon 
Responsible-Changed-By: linimon 
Responsible-Changed-When: Wed Apr 5 00:32:53 UTC 2006 
Responsible-Changed-Why:  

http://www.freebsd.org/cgi/query-pr.cgi?pr=63982 
>Unformatted:
