From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ralf Baechle DL5RB Subject: Re: AX25 mkiss interface not deleted when the serial port is removed Date: Tue, 29 Sep 2015 17:31:29 +0200 Message-ID: <20150929153129.GA31429@linux-mips.org> References: <5605828E.5010104@eclis.ch> Mime-Version: 1.0 Return-path: Content-Disposition: inline In-Reply-To: <5605828E.5010104@eclis.ch> Sender: linux-hams-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Jean-Christian de Rivaz Cc: linux-hams@vger.kernel.org On Fri, Sep 25, 2015 at 07:21:18PM +0200, Jean-Christian de Rivaz wrote: > On a embedded system we use AX25 over an USB serial port with the kissattach > command. For some hardware reason the microcontroller that act as a TNC and > USB CDC device can be rested while the system is running, causing a USB > disconnect of the USN CDC device and the removal of the corresponding serial > port in the kernel. But the ax0 interface is not removed in this case and > after a few seconds the kernel panic with the crash below: > > [] (skb_panic) from [] (skb_push+0x4c/0x50) > [] (skb_push) from [] (ax25_hard_header+0x34/0xf4 > [ax25]) > [] (ax25_hard_header [ax25]) from [] > (ax_header+0x38/0x40 [mkiss]) > [] (ax_header [mkiss]) from [] > (neigh_compat_output+0x8c/0xd8) > [] (neigh_compat_output) from [] > (ip_finish_output+0x2a0/0x914) > [] (ip_finish_output) from [] (ip_output+0xd8/0xf0) > [] (ip_output) from [] (ip_local_out_sk+0x44/0x48) skb_push is invoked via a code path that was conceptually completly broken and has been rewritten recently. So it would be great if you could retest with a recent release version preferably 4.2. I suspect this is not the cause but I'd like to exclude the possibility. Thanks, Ralf