Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751786AbeAPSLd (ORCPT + 1 other); Tue, 16 Jan 2018 13:11:33 -0500 Received: from mail-pl0-f53.google.com ([209.85.160.53]:34137 "EHLO mail-pl0-f53.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751741AbeAPSL2 (ORCPT ); Tue, 16 Jan 2018 13:11:28 -0500 X-Google-Smtp-Source: ACJfBovBvOj6oJGm/u1QQ6UFWi6CPXhutAGNdcdWnhI0NgPdiDphccSkTa0kPOb/KlsKeOPExDZDOsJ/XHo+0NwCFbU= MIME-Version: 1.0 In-Reply-To: References: <001a11c16b40d795350562e878cc@google.com> From: Dmitry Vyukov Date: Tue, 16 Jan 2018 19:11:07 +0100 Message-ID: Subject: Re: WARNING in can_rcv To: Marc Kleine-Budde Cc: syzbot , David Miller , linux-can@vger.kernel.org, LKML , netdev , Oliver Hartkopp , syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: On Tue, Jan 16, 2018 at 7:07 PM, Marc Kleine-Budde wrote: > On 01/16/2018 06:58 PM, syzbot wrote: >> Hello, >> >> syzkaller hit the following crash on >> a8750ddca918032d6349adbf9a4b6555e7db20da >> git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/master >> compiler: gcc (GCC) 7.1.1 20170620 >> .config is attached >> Raw console output is attached. >> C reproducer is attached >> syzkaller reproducer is attached. See https://goo.gl/kgGztJ >> for information about syzkaller reproducers >> >> >> IMPORTANT: if you fix the bug, please add the following tag to the commit: >> Reported-by: syzbot+4386709c0c1284dca827@syzkaller.appspotmail.com >> It will help syzbot understand when the bug is fixed. See footer for >> details. >> If you forward the report, please keep this part and the footer. >> >> device eql entered promiscuous mode >> ------------[ cut here ]------------ >> PF_CAN: dropped non conform CAN skbuf: dev type 65534, len 42, datalen 0 >> WARNING: CPU: 0 PID: 3650 at net/can/af_can.c:729 can_rcv+0x1c5/0x200 >> net/can/af_can.c:724 >> Kernel panic - not syncing: panic_on_warn set ... > > Invalid packages generate a warning (WARN_ONCE()), and you have > panic_on_warn active. Should we better silently drop these CAN packages? Hi, pr_warn_once() will be more appropriate. It prints a single line.