From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean-Christian de Rivaz Subject: Re: AX25 mkiss interface not deleted when the serial port is removed Date: Wed, 30 Sep 2015 02:29:35 +0200 Message-ID: <560B2CEF.4060209@eclis.ch> References: <5605828E.5010104@eclis.ch> <20150929153129.GA31429@linux-mips.org> Mime-Version: 1.0 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <20150929153129.GA31429@linux-mips.org> Sender: linux-hams-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="iso-8859-1"; format="flowed" To: Ralf Baechle DL5RB , linux-hams@trinnet.net Cc: linux-hams@vger.kernel.org, thomas@osterried.de Le 29. 09. 15 17:31, Ralf Baechle DL5RB a =E9crit : > On Fri, Sep 25, 2015 at 07:21:18PM +0200, Jean-Christian de Rivaz wro= te: > >> On a embedded system we use AX25 over an USB serial port with the ki= ssattach >> 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 correspondin= g serial >> port in the kernel. But the ax0 interface is not removed in this cas= e 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+0x34/0xf= 4 >> [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+0xd8/0x= f0) >> [] (ip_output) from [] (ip_local_out_sk+0x44/0x4= 8) > skb_push is invoked via a code path that was conceptually completly b= roken > and has been rewritten recently. So it would be great if you could r= etest > with a recent release version preferably 4.2. I suspect this is not = the > cause but I'd like to exclude the possibility. Hi Ralf, Unfortunately the kernel 4.3.0-rc3+ crash the same way. I suspect that=20 the real question is: what in ax25/mkiss make tty_ldisc_hangup() callin= g=20 tty_ldisc_open() on a serial port that no longer exists, and how to=20 avoid this ? Regards, Jean-Christian -- To unsubscribe from this list: send the line "unsubscribe linux-hams" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html