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From: "Denys Fedoryshchenko" <denys@visp•net.lb>
To: hadi@cyberus•ca
Cc: Jarek Poplawski <jarkao2@gmail•com>, netdev@vger•kernel.org
Subject: Re: circular locking, mirred, 2.6.24.2
Date: Thu, 6 Mar 2008 17:50:59 +0200	[thread overview]
Message-ID: <20080306143910.M91001@visp.net.lb> (raw)
In-Reply-To: <1204813634.4440.59.camel@localhost>

On Thu, 06 Mar 2008 09:27:14 -0500, jamal wrote
> On Thu, 2008-06-03 at 15:57 +0200, Denys Fedoryshchenko wrote:
> > I am able to reproduce this warning over this relatively simple shell 
script
> > on my Gentoo PC (2.6.25-rc3).
> > http://www.nuclearcat.com/files/bug_feb.txt
> >
> 
> That script looks pretty sane to me - nothing super-exciting. I suspect
> you eventually want them all to look like ifb1 on the egress.
> Do you see the same issue without the ifb1 speacial case?
Well, i am able to reproduce in much more trivial script. Tested 2.6.25-rc4 
also.

modprobe ifb
ifconfig ifb0 up
TC=/sbin/tc
$TC qdisc del dev eth0 ingress 1>/dev/null 2>/dev/null
$TC qdisc add dev eth0 ingress
${TC} filter add dev eth0 parent ffff: protocol ip prio 10 u32 \
      match u32 0 0 flowid 1:1 \
      action mirred egress redirect dev ifb0

> 
> > Probably it will help to debug issue for more experienced developers. 
Note:
> > it appears not immediately, second time i tested, it's appeared after 
while,
> > but in matter of seconds.
> 
> I wonder is there some latency from the moment you insmod ifb to the
> moment the tc rules take effect? Will it still happen if you dont 
> have modules? Also note, that lock dependency is a bit strange,
>  Jarek correct me if i am wrong; it seems to say: a packet received 
> on ingress of some e1000 (ethx) gets acted on by mirred which ends 
> grabbing lock of an ifb device - this part should be fine and no 
> need for the alarm. The alarm seems to be a result of a loopback 
> device that is being registered in between the two activities.
> i.e there are three devices affected with entirely different 
> locks(ethx, ifbx, and loopback). Smells like lockdep is getting it wrong?
No idea, i have strange lockup's on my systems where i have ifb, and that 
make me worry. And i feel it is directly related with my love to use ifb 
devices and way how i am using them.

> 
> > Note - it can stop traffic on PC completely. It is also seems crashed my 
> > desktop PC, i am not able to execute "tc qdisc del dev eth0 root".
> > The system hang completely. I had few similar issues on my PPPoE servers 
> > (with different scripts for shapers), that system hang, and even "reboot -
f" 
> > doesn't work sometimes.
> 
> This sounds like a different issue from above - when did this start 
> to happen? Is it at the same time as above warnings showing up?

Yes, it is different issue seems, it is rare to lockup system , and i will 
dig more, to understand how it is happening.

> 
> cheers,
> jamal
> 
> --
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--
Denys Fedoryshchenko
Technical Manager
Virtual ISP S.A.L.


  reply	other threads:[~2008-03-06 15:51 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-24 22:20 circular locking, mirred, 2.6.24.2 Denys Fedoryshchenko
2008-02-25  9:56 ` Jarek Poplawski
2008-02-25 10:48   ` Denys Fedoryshchenko
2008-02-25 11:39     ` Jarek Poplawski
2008-03-05 10:45       ` Denys Fedoryshchenko
2008-03-05 13:54         ` [BUG] Probably lockdep bug " Jarek Poplawski
2008-03-06  9:41           ` Jarek Poplawski
2008-03-06 13:40         ` Jarek Poplawski
2008-03-06 13:57           ` Denys Fedoryshchenko
2008-03-06 14:27             ` jamal
2008-03-06 15:50               ` Denys Fedoryshchenko [this message]
2008-03-06 20:25                 ` Jarek Poplawski
2008-03-06 20:56                   ` jamal
2008-03-06 22:12                     ` Jarek Poplawski
2008-03-06 23:43                       ` Denys Fedoryshchenko
2008-03-07  0:09                         ` jamal
2008-03-07  0:15                           ` Denys Fedoryshchenko
2008-03-07  0:25                             ` jamal
2008-03-07  9:31                         ` Jarek Poplawski
2008-03-07 10:19                           ` Denys Fedoryshchenko
2008-03-07 10:48                             ` Jarek Poplawski
2008-03-07 14:58                             ` jamal
2008-03-06 20:44                 ` jamal
2008-03-06 13:59           ` jamal
2008-03-06 17:56             ` Jarek Poplawski
2008-03-06 20:48               ` jamal
2008-03-06 21:40                 ` Jarek Poplawski
2008-03-06 23:40                   ` jamal
2008-03-07  7:51                     ` Jarek Poplawski
2008-03-07  8:32                       ` Jarek Poplawski
2008-03-07 13:53                       ` jamal
2008-03-08  8:46                         ` Jarek Poplawski
2008-03-08  8:58                           ` Jarek Poplawski
2008-03-08  9:56                             ` Denys Fedoryshchenko
2008-03-08 10:16                             ` Denys Fedoryshchenko
2008-03-08 10:43                               ` Jarek Poplawski
2008-03-08 10:52                                 ` Jarek Poplawski
2008-03-08 11:09                                   ` Denys Fedoryshchenko
2008-03-08 12:02                                     ` Jarek Poplawski
2008-03-19  0:46                                       ` Denys Fedoryshchenko
2008-03-19  7:34                                         ` [PATCH][NET] ifb: set separate lockdep classes for queue locks Jarek Poplawski
2008-03-19 11:34                                           ` jamal
2008-03-19 12:20                                             ` Jarek Poplawski
2008-03-20 22:37                                           ` David Miller
2008-03-21  0:03                                             ` [PATCH take2][NET] " Jarek Poplawski
2008-03-21  0:05                                               ` David Miller
2008-03-21  0:15                                               ` Jarek Poplawski

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