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Wed, 29 Jul 2026 12:25:13 +0000 (GMT) Received: from [9.224.94.95] (unknown [9.224.94.95]) by smtpav03.fra02v.mail.ibm.com (Postfix) with ESMTP; Wed, 29 Jul 2026 12:25:13 +0000 (GMT) Message-ID: Date: Wed, 29 Jul 2026 14:25:12 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net] dibs: fix use-after-free of dmb_node in loopback attach/detach/unregister To: Hidayath Khan , davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, alibuda@linux.alibaba.com, dust.li@linux.alibaba.com, sidraya@linux.ibm.com, wenjia@linux.ibm.com, mjambigi@linux.ibm.com, Rahul Chandelkar Cc: tonylu@linux.alibaba.com, guwen@linux.alibaba.com, horms@kernel.org, hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, borntraeger@linux.ibm.com, svens@linux.ibm.com, pasic@linux.ibm.com, gbayer@linux.ibm.com, andrew+netdev@lunn.ch, netdev@vger.kernel.org, linux-s390@vger.kernel.org, linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org References: <20260727093530.968834-1-hidayath@linux.ibm.com> Content-Language: en-US From: Alexandra Winter In-Reply-To: <20260727093530.968834-1-hidayath@linux.ibm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-ORIG-GUID: 4MwX9pVB33iqrYqOxD5A_w2oVIBToZWb X-Proofpoint-Spam-Info: AW1haW4tMjYwNzI5MDEwMiBTYWx0ZWRfX20ynG5a+0ss0 3ueQNYLWusR/X51uqNSB7pUTKaoEDXJNC8b1GomI6E2Ecy5Y3Xi+iUcAckmnrcP7w4kdVJ0pVkR p9SZgrt+rCOquIEHc+TjfnCN6/I4PUs= X-Authority-Analysis: v=2.4 cv=E/z9Y6dl c=1 sm=1 tr=0 ts=6a69f12e cx=c_pps a=aDMHemPKRhS1OARIsFnwRA==:117 a=aDMHemPKRhS1OARIsFnwRA==:17 a=IkcTkHD0fZMA:10 a=RAioF0-LDSMA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=RzCfie-kr_QcCd8fBx8p:22 a=VwQbUJbxAAAA:8 a=o8dFRQB0AAAA:8 a=DAb8WqUzKgD87k8msboA:9 a=QEXdDO2ut3YA:10 a=D5cU4ZU6l4KboW5xFU7l:22 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNzI5MDEwMiBTYWx0ZWRfX7GlIJnWnzeAG wRWEFtaAcINncWSZOygZRlhosCpKUIXh3eSm2yD2CKO0AMH1A6C+PWJu1aknfG0U/UNrVfDPpru GbgxnZ4EdvujGeMjyzmWoT0KV4YRZCVUc1ORePy9vjMPnO1ydYWyYrq+l2j0QVfOsRBWfBrNnku Ef37C1dWe4fKITN+Vg+Sqo4tOv8CdumpsF38j0TxLWCMSCYSm7BsPHlIYBHzHkfOnXF1KqN7Ryt VwZ9T4PkQw6jgic7tflXvyzs1+xceVzFql8SaoQib8+KGUD7K0r9je2egP7v3AMCx2SU/lQPsD4 ZxCJCE0oHGWKX56HC32Em5KPQ39AOj/Pg8u9eHFq+xTKUN1DXgF7IJSTlO00SzIjdaRSNXFZhOy DhqjZuqcpDNLrB+0l3MittWSMovZrKRjsAZVPIm6DfVOzKT5oDiBwxdQbf6KWfLAP/LqHuE0dOp uD0H1ZbCqBXVo/6HUOA== X-Proofpoint-GUID: jdfYQMc6znUxFmTKOdJGrdkhrh0lR4V6 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-07-29_04,2026-07-28_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 priorityscore=1501 spamscore=0 clxscore=1015 phishscore=0 lowpriorityscore=0 bulkscore=0 malwarescore=0 impostorscore=0 suspectscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2607290102 On 27.07.26 11:35, Hidayath Khan wrote: > dibs_lo_attach_dmb(), dibs_lo_detach_dmb() and dibs_lo_unregister_dmb() > look up the dmb_node under dmb_ht_lock, drop the lock and only then > operate on the node's refcount. Nothing keeps the node alive across > that window: __dibs_lo_unregister_dmb() removes the node from the hash > table under the write lock and immediately frees it. > I had lost track of this, but Rahul Chandelkar had already proposed a similar patch [1] for this issue, but never followed up with a v2. Rahul, Hidayath, Would it be ok for both of you to add Reported-by: Rahul Chandelkar [1] https://lore.kernel.org/netdev/4gRZFl1CWvz2x9j@mail.spacemail.com/