From: Guillaume Nault <g.nault@alphalink.fr>
To: Cong Wang <xiyou.wangcong@gmail.com>
Cc: nuclearcat@nuclearcat.com,
Linux Kernel Network Developers <netdev@vger.kernel.org>
Subject: Re: 4.6.3, pppoe + shaper workload, skb_panic / skb_push / ppp_start_xmit
Date: Thu, 28 Jul 2016 13:09:48 +0200 [thread overview]
Message-ID: <20160728110948.GA3046@alphalink.fr> (raw)
In-Reply-To: <CAM_iQpWuCw6Bgm=1BWMkoFkuav5xV+FyKPq0Ef+3N_qpQqv=AA@mail.gmail.com>
On Tue, Jul 12, 2016 at 10:31:18AM -0700, Cong Wang wrote:
> On Mon, Jul 11, 2016 at 12:45 PM, <nuclearcat@nuclearcat.com> wrote:
> > Hi
> >
> > On latest kernel i noticed kernel panic happening 1-2 times per day. It is
> > also happening on older kernel (at least 4.5.3).
> >
> ...
> > [42916.426463] Call Trace:
> > [42916.426658] <IRQ>
> >
> > [42916.426719] [<ffffffff81843786>] skb_push+0x36/0x37
> > [42916.427111] [<ffffffffa00e8ce5>] ppp_start_xmit+0x10f/0x150
> > [ppp_generic]
> > [42916.427314] [<ffffffff81853467>] dev_hard_start_xmit+0x25a/0x2d3
> > [42916.427516] [<ffffffff818530f2>] ?
> > validate_xmit_skb.isra.107.part.108+0x11d/0x238
> > [42916.427858] [<ffffffff8186dee3>] sch_direct_xmit+0x89/0x1b5
> > [42916.428060] [<ffffffff8186e142>] __qdisc_run+0x133/0x170
> > [42916.428261] [<ffffffff81850034>] net_tx_action+0xe3/0x148
> > [42916.428462] [<ffffffff810c401a>] __do_softirq+0xb9/0x1a9
> > [42916.428663] [<ffffffff810c4251>] irq_exit+0x37/0x7c
> > [42916.428862] [<ffffffff8102b8f7>] smp_apic_timer_interrupt+0x3d/0x48
> > [42916.429063] [<ffffffff818cb15c>] apic_timer_interrupt+0x7c/0x90
>
> Interesting, we call a skb_cow_head() before skb_push() in ppp_start_xmit(),
> I have no idea why this could happen.
>
The skb is corrupted: head is at ffff8800b0bf2800 while data is at
ffa00500b0bf284c.
Figuring out how this corruption happened is going to be hard without a
way to reproduce the problem.
Denys, can you confirm you're using a vanilla kernel?
Also I guess the ppp devices and tc settings are handled by accel-ppp.
If so, can you share more info about your setup (accel-ppp.conf, radius
attributes, iptables...) so that I can try to reproduce it on my
machines?
Regards
Guillaume
next prev parent reply other threads:[~2016-07-28 11:09 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-11 19:45 4.6.3, pppoe + shaper workload, skb_panic / skb_push / ppp_start_xmit nuclearcat
2016-07-12 17:31 ` Cong Wang
2016-07-12 18:03 ` nuclearcat
2016-07-12 18:05 ` Cong Wang
2016-07-12 18:13 ` nuclearcat
2016-07-28 11:09 ` Guillaume Nault [this message]
2016-07-28 11:28 ` Denys Fedoryshchenko
2016-08-01 20:54 ` Guillaume Nault
2016-08-01 20:59 ` Guillaume Nault
2016-08-01 22:52 ` Denys Fedoryshchenko
2016-08-08 11:25 ` Denys Fedoryshchenko
2016-08-08 21:05 ` Guillaume Nault
2016-08-17 11:54 ` Denys Fedoryshchenko
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