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Wed, 29 Jul 2026 12:50:02 +0000 (GMT) Received: from [9.124.223.194] (unknown [9.124.223.194]) by smtpav06.dal12v.mail.ibm.com (Postfix) with ESMTP; Wed, 29 Jul 2026 12:50:02 +0000 (GMT) Message-ID: <9d2d6c92-2d5c-4b12-af1e-78062da8730f@linux.ibm.com> Date: Wed, 29 Jul 2026 18:20:00 +0530 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: Alexandra Winter , 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-GB From: Hidayathulla Khan I In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Proofpoint-Spam-Info: AW1haW4tMjYwNzI5MDEwNiBTYWx0ZWRfX1AYSUqo6/c80 M0BgEyg3CBrWweE98C8BeOR3FPOjPNg+AT8CRAyalOqQSWsmewiJpnMkwZBUlATn44GSce7fhL+ ESZgUACdrGZMIUd4qEJmvNyUi8ro9Xw= X-Proofpoint-GUID: TPgpCcYfjCWYvfEwRzKe4HL9ZrKnIPDL X-Proofpoint-ORIG-GUID: mkX1yKPkKuGxTemBW9iafx7wxFYvCAOA X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNzI5MDEwNiBTYWx0ZWRfX/thqRPL/jnWj ymKoEeg6bz4QKgf8FV4ZxoQyPjNV1+m20pxVUFY+tOn7eOQr27vwQZflsGabm0I+GrXvK6Mnlwt CMTDh6T9TL8QnoWhFDqw93SAlXpoE/kLmc1r6QaBP1yudttZRoRG/e+ykWreiIUE1/v3tosq3qN vfjq43PLIlLaFEP3hWxPmY9aAPIFIimdktj1zUb0bwiwKdRBwwxDT0DsxPt1DaKYCO5y9iluolR BzfdtTJWZCw67uhUjlJ3K9vOknvvlQ3Lw5vWI6uJMrKuJO1WYoFLql5kfExujQ4dRmZYEfrYtf5 XK390xvr/G+v3kuolNwdhisBd7ClTWDAcbjtRZMDAh04QizmOKYaeWbnDsaBs0Ixhw2lBR0a+jN ayClPgVRyA1ENz5vJijHivCPCiMmjVIBmxQnn76SqprqkeqzhIJ0hFK26iC0WGpsLjC878jchy0 JSdtE7H3wNsQEsKBMnw== X-Authority-Analysis: v=2.4 cv=X5Vi7mTe c=1 sm=1 tr=0 ts=6a69f706 cx=c_pps a=aDMHemPKRhS1OARIsFnwRA==:117 a=aDMHemPKRhS1OARIsFnwRA==:17 a=IkcTkHD0fZMA:10 a=RAioF0-LDSMA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=Y2IxJ9c9Rs8Kov3niI8_:22 a=VwQbUJbxAAAA:8 a=o8dFRQB0AAAA:8 a=_9ao5c0ydNkKcCpahgwA:9 a=QEXdDO2ut3YA:10 a=D5cU4ZU6l4KboW5xFU7l:22 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 clxscore=1011 impostorscore=0 lowpriorityscore=0 phishscore=0 priorityscore=1501 malwarescore=0 spamscore=0 suspectscore=0 bulkscore=0 adultscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2607290106 On 29/07/26 5:55 pm, Alexandra Winter wrote: > > 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 Sure, happy to add Reported-by: Rahul Chandelkar in v2. > > > [1] https://lore.kernel.org/netdev/4gRZFl1CWvz2x9j@mail.spacemail.com/ >