Bug 527748

Summary: /proc/net/dev sometimes contains bogus values (BCM5706)
Product: Red Hat Enterprise Linux 5 Reporter: Flavio Leitner <fleitner>
Component: kernelAssignee: Flavio Leitner <fleitner>
Status: CLOSED ERRATA QA Contact: Red Hat Kernel QE team <kernel-qe>
Severity: medium Docs Contact:
Priority: medium    
Version: 5.4CC: agospoda, dzickus, emcnabb, jfeeney, mchan, tao, vgoyal
Target Milestone: rc   
Target Release: ---   
Hardware: All   
OS: Linux   
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: 515274 Environment:
Last Closed: 2010-03-30 07:31:58 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Bug Depends On: 515274    
Bug Blocks:    
Description Flags
patch for RHEL5u5 none

Description Flavio Leitner 2009-10-07 15:11:31 UTC
+++ This bug was initially created as a clone of Bug #515274 +++

The network utilization graphics in ganglia report shows peaks
of petabytes, when the network interface is just Gigabit eth.

Broadcom developer (Michael Chan) confirmed that NIC BCM5706 and
BCM5708 are very similar in design so BCM5706 could suffer the same
problem described below:

The statistics block DMA on 5708 can be messed up occasionally on the
average of about once per hour.  If the user is reading the counters
within one second after the corruption, the counters will be all
messed up.  One second later, the counters will be ok again until the
next corruption occurs.

The workaround is to disable the periodic statistics DMA.  Instead,
we manually trigger the DMA once a second in bnx2_timer().  This
manual trigger of the DMA avoids the problem.

Applied on net-next-2.6:

commit 61d9e3fa7eacabfb7879e3da91709f1a5420c507
Author: Michael Chan <mchan@broadcom.com>
Date:   Fri Aug 21 16:20:46 2009 +0000

    bnx2: Apply BROKEN_STATS workaround to 5706 and 5708.

    Add flag to expand the workaround to both chips.

    Signed-off-by: Michael Chan <mchan@broadcom.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>

Comment 1 Flavio Leitner 2009-10-07 19:18:57 UTC
Created attachment 364026 [details]
patch for RHEL5u5

Comment 3 RHEL Program Management 2009-10-07 20:08:15 UTC
This request was evaluated by Red Hat Product Management for inclusion in a Red
Hat Enterprise Linux maintenance release.  Product Management has requested
further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed
products.  This request is not yet committed for inclusion in an Update

Comment 6 Don Zickus 2009-10-21 19:13:45 UTC
in kernel-2.6.18-170.el5
You can download this test kernel from http://people.redhat.com/dzickus/el5

Please do NOT transition this bugzilla state to VERIFIED until our QE team
has sent specific instructions indicating when to do so.  However feel free
to provide a comment indicating that this fix has been verified.

Comment 9 errata-xmlrpc 2010-03-30 07:31:58 UTC
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.