From mboxrd@z Thu Jan  1 00:00:00 1970
From: Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: Fw: [Bug 197099] New: Kernel panic in interrupt [l2tp_ppp]
Date: Mon, 02 Oct 2017 06:56:06 -0700
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Cc: Stephen Hemminger <stephen@networkplumber.org>,
        netdev@vger.kernel.org
To: James Chapman <jchapman@katalix.com>, svimik@gmail.com
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CC svimik@gmail.com so that he is aware of this netdev thread.

On Mon, 2017-10-02 at 14:32 +0100, James Chapman wrote:
> This seems to be a NULL pointer exception caused by tunnel->sock being
> NULL at the call to bh_lock_sock() in l2tp_xmit_skb() at
> l2tp_core.c:1135.
> 
> tunnel->sock is set NULL in l2tp_core's tunnel socket destructor.
> 
> At the moment, I don't understand how this happens because
> pppol2tp_xmit() does a sock_hold() on the tunnel socket before
> l2tp_xmit_skb() is called. I'm still looking at this.
> 
> Has this problem only recently started happening?
> 
> 
> 
> 
> 
> On 1 October 2017 at 18:21, Stephen Hemminger
> <stephen@networkplumber.org> wrote:
> >
> >
> > Begin forwarded message:
> >
> > Date: Sun, 01 Oct 2017 16:22:33 +0000
> > From: bugzilla-daemon@bugzilla.kernel.org
> > To: stephen@networkplumber.org
> > Subject: [Bug 197099] New: Kernel panic in interrupt [l2tp_ppp]
> >
> >
> > https://bugzilla.kernel.org/show_bug.cgi?id=197099
> >
> >             Bug ID: 197099
> >            Summary: Kernel panic in interrupt [l2tp_ppp]
> >            Product: Networking
> >            Version: 2.5
> >     Kernel Version: 4.8.13-1.el6.elrepo.x86_64
> >           Hardware: x86-64
> >                 OS: Linux
> >               Tree: Mainline
> >             Status: NEW
> >           Severity: normal
> >           Priority: P1
> >          Component: Other
> >           Assignee: stephen@networkplumber.org
> >           Reporter: svimik@gmail.com
> >         Regression: No
> >
> > Created attachment 258685
> >   --> https://bugzilla.kernel.org/attachment.cgi?id=258685&action=edit
> > stacktrace screenshot
> >
> > Hello!
> >
> > Getting kernel panics on multiple servers. Since it mentions l2tp_core,
> > l2tp_ppp and ppp_generic, I decided to report it to Networking (correct me if
> > I'm wrong).
> >
> > Unfortunately I'm still struggling with making kdump work, so the trace
> > screenshot is all I have at this moment. The only hope is that this stacktrace
> > means something to the guys that wrote the code.
> >
> > --
> > You are receiving this mail because:
> > You are the assignee for the bug.