From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Murat Sezgin" Subject: kernel panic in pppoe_release Date: Thu, 3 Sep 2015 12:14:32 -0700 Message-ID: <006f01d0e67c$c3d53f10$4b7fbd30$@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE To: Return-path: Received: from smtp.codeaurora.org ([198.145.29.96]:46984 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751808AbbICTOd convert rfc822-to-8bit (ORCPT ); Thu, 3 Sep 2015 15:14:33 -0400 Received: from MSEZGIN (qf-scl1nat.qualcomm.com [207.114.132.30]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: msezgin@smtp.codeaurora.org) by smtp.codeaurora.org (Postfix) with ESMTPSA id E9ABC141880 for ; Thu, 3 Sep 2015 19:14:32 +0000 (UTC) Content-Language: en-us Sender: netdev-owner@vger.kernel.org List-ID: Hi all, I have already sent this email to linux-ppp group, but I have not recei= ved any response yet. So, I want to send it to this group as well, because = it is most likely a netdev issue in pppoe kernel driver. I see the bug in the below email discussion on the kernel that we are currently using (3.4.103) with our openwrt distribution. https://www.mail-archive.com/netdev@vger.kernel.org/msg70367.html I did some debug on this and I see that the ref count of the po->pppoe_= dev doesn=92t go to zero before releasing it with dev_put() and set its val= ue to NULL. I also found the below patches from openwrt patch site for 3.18 and 4.0 kernels which can be applicable to our kernel.=20 https://dev.openwrt.org/changeset/45653 But as described in the netdev mail-archive link above, it doesn=92t so= lve this issue completely and we still see the crash. I just wonder , if th= e proposed patch by =93Denys Fedoryshchenko=94, which is below, fixes thi= s issue completely. =A0=A0=A0=A0=A0=A0=A0 pppox_unbind_sock(sk); =A0=A0=A0=A0=A0=A0=A0 +/* Signal the death of the socket. */ =A0=A0=A0=A0=A0=A0=A0 +sk->sk_state =3D PPPOX_DEAD; Do you have a conclusion on this bug? Is it safe to get this patch alon= g with the other workqueue patches? Regards, Murat