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Thu, 16 Apr 2020 10:28:27 +0000 Received: from pps.filterd (userp3030.oracle.com [127.0.0.1]) by userp3030.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 03GAHsZJ099521; Thu, 16 Apr 2020 10:26:26 GMT Received: from userv0121.oracle.com (userv0121.oracle.com [156.151.31.72]) by userp3030.oracle.com with ESMTP id 30dynya2y6-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 16 Apr 2020 10:26:26 +0000 Received: from abhmp0013.oracle.com (abhmp0013.oracle.com [141.146.116.19]) by userv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 03GAQOEY025630; Thu, 16 Apr 2020 10:26:24 GMT Received: from kadam (/41.57.98.10) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Thu, 16 Apr 2020 03:26:24 -0700 Date: Thu, 16 Apr 2020 13:26:12 +0300 From: Dan Carpenter To: Andrii Nakryiko Cc: Daniel Borkmann , syzbot , ast@kernel.org, bpf@vger.kernel.org, john.fastabend@gmail.com, kafai@fb.com, kpsingh@chromium.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, songliubraving@fb.com, syzkaller-bugs@googlegroups.com, yhs@fb.com Subject: Re: WARNING in bpf_cgroup_link_release Message-ID: <20200416102612.GO1163@kadam> References: <000000000000500e6f05a34ecc01@google.com> <4ba5ee0c-ec81-8ce3-6681-465e34b98a93@iogearbox.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9592 signatures=668686 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxlogscore=896 suspectscore=0 malwarescore=0 phishscore=0 spamscore=0 adultscore=0 mlxscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2004160071 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9592 signatures=668686 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 adultscore=0 clxscore=1011 malwarescore=0 bulkscore=0 priorityscore=1501 lowpriorityscore=0 mlxscore=0 phishscore=0 spamscore=0 impostorscore=0 suspectscore=0 mlxlogscore=965 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2003020000 definitions=main-2004160072 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 15, 2020 at 09:51:40AM -0700, 'Andrii Nakryiko' via syzkaller-bugs wrote: > On 4/15/20 4:57 AM, Daniel Borkmann wrote: > > On 4/15/20 8:55 AM, syzbot wrote: > > > Hello, > > > > > > syzbot found the following crash on: > > > > Andrii, ptal. > > > > > HEAD commit:    1a323ea5 x86: get rid of 'errret' argument to > > > __get_user_x.. > > > git tree:       bpf-next > > > console output: https://urldefense.proofpoint.com/v2/url?u=https-3A__syzkaller.appspot.com_x_log.txt-3Fx-3D148ccb57e00000&d=DwICaQ&c=5VD0RTtNlTh3ycd41b3MUw&r=vxqvl81C2rT6GOGdPyz8iQ&m=T2Ez0XmyIpHmEa_MPTTUOh61jMDXqwETtTaTbSe-2M4&s=-6XBbsNV1O4X5flrx4Yssfjc56d0qeSHgwHhd92UPJc&e= > > > kernel config: https://urldefense.proofpoint.com/v2/url?u=https-3A__syzkaller.appspot.com_x_.config-3Fx-3D8c1e98458335a7d1&d=DwICaQ&c=5VD0RTtNlTh3ycd41b3MUw&r=vxqvl81C2rT6GOGdPyz8iQ&m=T2Ez0XmyIpHmEa_MPTTUOh61jMDXqwETtTaTbSe-2M4&s=s5-1AlWtSiBvo66WN4_UXoXMGIGIqsoUCrmAnxNnfX0&e= > > > dashboard link: https://urldefense.proofpoint.com/v2/url?u=https-3A__syzkaller.appspot.com_bug-3Fextid-3D8a5dadc5c0b1d7055945&d=DwICaQ&c=5VD0RTtNlTh3ycd41b3MUw&r=vxqvl81C2rT6GOGdPyz8iQ&m=T2Ez0XmyIpHmEa_MPTTUOh61jMDXqwETtTaTbSe-2M4&s=hAA0702qJH5EwRwvG0RKmj8FwIRm1O8hvmoS7ne5Dls&e= > > > compiler:       gcc (GCC) 9.0.0 20181231 (experimental) > > > > > > Unfortunately, I don't have any reproducer for this crash yet. > > > > > > IMPORTANT: if you fix the bug, please add the following tag to the > > > commit: > > > Reported-by: syzbot+8a5dadc5c0b1d7055945@syzkaller.appspotmail.com > > > > > > ------------[ cut here ]------------ > > > WARNING: CPU: 0 PID: 25081 at kernel/bpf/cgroup.c:796 > > > bpf_cgroup_link_release+0x260/0x3a0 kernel/bpf/cgroup.c:796 > > This warning is triggered due to __cgroup_bpf_detach returning an error. It > can do it only in two cases: either attached item is not found, which from > starting at code some moreI don't see how that can happen. The other reason > - kmalloc() failing to allocate memory for new effective prog array. If you look at the log file then this was allocation fault injection in bpf_prog_array_alloc(). https://syzkaller.appspot.com/x/log.txt?x=148ccb57e00000 regards, dan carpenter