Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752798AbeADTBL (ORCPT + 1 other); Thu, 4 Jan 2018 14:01:11 -0500 Received: from mail-ot0-f195.google.com ([74.125.82.195]:40374 "EHLO mail-ot0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750959AbeADTBK (ORCPT ); Thu, 4 Jan 2018 14:01:10 -0500 X-Google-Smtp-Source: ACJfBosdNwML2G5FCrpvPA2E0YBZdV/s8iP8aT8zbG8uPeaczZLnfWd1GsJREMPlHHJForn7kVGhSg== Subject: Re: WARNING in ion_ioctl To: Dmitry Vyukov , Greg KH Cc: syzbot , arve@android.com, devel@driverdev.osuosl.org, LKML , maco@android.com, sumit.semwal@linaro.org, syzkaller-bugs@googlegroups.com, tkjos@android.com References: <20180104140627.GB17490@kroah.com> From: Laura Abbott Message-ID: Date: Thu, 4 Jan 2018 11:01:06 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: On 01/04/2018 06:13 AM, Dmitry Vyukov wrote: > On Thu, Jan 4, 2018 at 3:06 PM, Greg KH wrote: >> On Thu, Jan 04, 2018 at 05:57:01AM -0800, syzbot wrote: >>> Hello, >>> >>> syzkaller hit the following crash on >>> 71ee203389f7cb1c1927eab22b95baa01405791c >>> 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+fa2d5f63ee5904a0115a@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. >>> >>> audit: type=1400 audit(1514734723.062:7): avc: denied { map } for >>> pid=3502 comm="syzkaller809746" path="/root/syzkaller809746698" dev="sda1" >>> ino=16481 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 >>> tcontext=unconfined_u:object_r:user_home_t:s0 tclass=file permissive=1 >>> WARNING: CPU: 0 PID: 3502 at drivers/staging/android/ion/ion-ioctl.c:73 >>> ion_ioctl+0x2db/0x380 drivers/staging/android/ion/ion-ioctl.c:73 >>> Kernel panic - not syncing: panic_on_warn set ... >> >> This is to be expected when you pass in a crappy ion ioctl structure. >> >> So don't do that :) >> >> Yeah, it's a harsh warning, but I think the userspace developers like it >> to ensure they got their implementation correct. >> >> After the warning is thrown, all keeps working just fine. > > Hi Greg, > > Or, don't do WARNINGs on EINVAL and do pr_warn instead, as useful but > also enables automated kernel testing with non-tainted reports, which > is kinda a useful property. > From past experience, pr_warn was too subtle for some developers but I'm more interested in the fuzzing at this point so I'll see about just switching it to a pr_warn_once. Thanks, Laura