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Message-Id: <200801091206.m09C6QeB002727@www.freebsd.org>
Date: Wed, 9 Jan 2008 12:06:26 GMT
From: ke Wallebom <ake@ake.nu>
To: freebsd-gnats-submit@FreeBSD.org
Subject: page fault in em taskq with polling enabled
X-Send-Pr-Version: www-3.1
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>Number:         119487
>Category:       kern
>Synopsis:       [em] page fault in em taskq with polling enabled
>Confidential:   no
>Severity:       serious
>Priority:       low
>Responsible:    freebsd-bugs
>State:          closed
>Quarter:        
>Keywords:       
>Date-Required:  
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Wed Jan 09 12:10:02 UTC 2008
>Closed-Date:    Wed Jul 14 12:51:36 UTC 2010
>Last-Modified:  Wed Jul 14 12:51:36 UTC 2010
>Originator:     ke Wallebom
>Release:        7.0 RC1
>Organization:
>Environment:
FreeBSD dunder 7.0-RC1 FreeBSD 7.0-RC1 #2: Tue Jan  8 22:29:24 CET 2008     removed@dunder:/usr/obj/usr/src/sys/CUSTOM  amd64

>Description:
I got a page fault with 'current process' being 'em0 taskq' while
transferring about 200 GB of data from an ftp server to my FreeBSD box
via Gigabit LAN.

I had compiled my kernel with DEVICE_POLLING and HZ=2000, and
kern.polling.enable was set to 1 (I noticed later that this was deprecated).

The files were transfered onto a ZFS pool on a GELI-device (1TB SATA2-drive).

After transferring 150 GB i got the above error and the kernel panic'ed.

Sadly, I can't remember the whole error message.

More about the machine:

Core 2 Duo E6750
4 GB RAM
Three Intel PRO/1000 GT Desktop NICs (Single port cards)
>How-To-Repeat:
I really don't know...

Hasn't happened again - but I have now recompiled the kernel with just
'POLLING' set, using default HZ now. And now i don't enable polling via
sysctl but via ifconfig xxx polling.

Transfered 180 GB and did not crash. So I guess I'm just reporting this
as a curiosity for the em driver developer(s).
>Fix:
Decrease the HZ value? 
Set polling via ifconfig instead of kern.polling.enable?

>Release-Note:
>Audit-Trail:

From: "Remko Lodder" <remko@elvandar.org>
To: =?iso-8859-1?Q?=C5ke_Wallebom?= <ake@ake.nu>
Cc: freebsd-gnats-submit@freebsd.org
Subject: Re: kern/119487: page fault in em taskq with polling enabled
Date: Wed, 9 Jan 2008 17:29:30 +0100 (CET)

 One of the things: dont use polling with em cards, it's not needed and
 could have negative impact on your machine. Also, if you get a crash,
 please try to obtain a kernel crashdump so that we can see what is going
 on and understand it and fix it ;-)
 
 You can see more details about that on
 http://www.freebsd.org/doc/en/books/developers-handbook/kerneldebug.html
 
 Without it, it's just looking in the blind.
 
 In addition; can you test this without polling enabled at all?
 
 Cheers,
 Remko
 
 -- 
 /"\   Best regards,                      | remko@FreeBSD.org
 \ /   Remko Lodder                       | remko@EFnet
  X    http://www.evilcoder.org/          |
 / \   ASCII Ribbon Campaign              | Against HTML Mail and News
 
 
State-Changed-From-To: open->feedback 
State-Changed-By: linimon 
State-Changed-When: Mon Jan 14 07:46:17 UTC 2008 
State-Changed-Why:  
Note that submitter was asked for feedback. 

http://www.freebsd.org/cgi/query-pr.cgi?pr=119487 

From: "Anatoly Y." <snelius@tsu.ru>
To: bug-followup@FreeBSD.org
Cc:  
Subject: Re: kern/119487: [em] page fault in em taskq with polling enabled
Date: Mon, 28 Apr 2008 15:09:34 +0700

 Yep. I have this bug on my production router.
 fbsd 7.0STABLE (Mon Apr 21 14:20:00)
 amd64
 
 crash with ifconfig em1 polling :(
 HZ=1000
 
 P.S. I'll attempt crash dump.
 
 -- 
 Anatoly Y. aka Snelius | AY254-RIPE

 [bugmeister note: text from a misfiled followup by lev@FreeBSD.org has
  been moved to 121928]

State-Changed-From-To: feedback->closed 
State-Changed-By: remko 
State-Changed-When: Wed Jul 14 12:51:35 UTC 2010 
State-Changed-Why:  
I do not recall seeing a crashdump, close the PR. 

http://www.freebsd.org/cgi/query-pr.cgi?pr=119487 
>Unformatted:
