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Wed, 21 Oct 2026 08:10:30 +0000 (GMT) Received: from [9.224.68.68] (unknown [9.224.68.68]) by smtpav03.fra02v.mail.ibm.com (Postfix) with ESMTP; Wed, 21 Oct 2026 08:10:30 +0000 (GMT) Message-ID: <22744f49-b45a-458c-828d-bc19a5f06aa9@linux.ibm.com> Date: Wed, 21 Oct 2026 10:10:30 +0200 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] iucv: fix lockless sk_for_each in afiucv_netdev_event To: Haoran Wang , "David S. Miller" , Jakub Kicinski , Paolo Abeni , Eric Dumazet Cc: netdev@vger.kernel.org, Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org References: <179241612354.5916.12881323209252769976@whr> Content-Language: en-US From: Alexandra Winter In-Reply-To: <179241612354.5916.12881323209252769976@whr> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-Reinject: loops=2 maxloops=12 X-Authority-Analysis: v=2.4 cv=X63Hu2Te c=1 sm=1 tr=0 ts=6ad8737c cx=c_pps a=aDMHemPKRhS1OARIsFnwRA==:117 a=aDMHemPKRhS1OARIsFnwRA==:17 a=IkcTkHD0fZMA:10 a=660iZSQnnn4A:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=Y2IxJ9c9Rs8Kov3niI8_:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=_eNH3aichsnAWiy1AtcA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-ORIG-GUID: ryKGVAkseroqDH-QuvbKb0wrxGw7UBsb X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYxMDIxMDAzMCBTYWx0ZWRfX+1jlpldPkb1d L0scCkAIQTS+ac6dnYtWj5h9yJwiNW8Z68t/CfK+Ykdfzz9KeuvL7vOGv3C3Ww70kTQUO0QzCOy y5Ct0PsDT79AfSD4MGIsQKcdUTt+zmzOa0ay9b3FBm04lIXsjfPrQtDEwAqCFEW2Coup1uHCAbZ Ed/BiCmQ7APJ1l8W1oGzxHOOzYFENNQPjDtoegbnjO88+X0NIW6SBMv4YJpSaead8cOxE8y+yZa nUru2PYsyjYLwjljsU9qb0C/4faN4X9yYsT2E/zk6dsQYUlmPfUnWGHxM8sJ3R/EIFOalOXcbLe rfZXP4i10XILgEMTgynCvSemnfDlhCEbcpKaf+62iaOcyL+c8l3gP1alhJgyQ3bkTlXgxmER1F9 a1WWFRl/MtYhz8Drd9AYp50sIoeNhH+eSviWRRZkM+uWBpzE4K7xfgqJn7/nJducuIgZ6HHPNXr La6aabm2H6+dwhrfZ7w== X-Proofpoint-Spam-Info: AW1haW4tMjYxMDIxMDAzMCBTYWx0ZWRfX+MnvtKtY0cKr I/OV2vqwvAbvPwkJofKLlICGMjXeR53iBlrzVS4WRMHgN7OTsPzM+1+Be3aBgZTroK93UxFRkpX aJypl89Gx8SSYI3o8JqjPtImrLFdGxc= X-Proofpoint-GUID: nTBtUMs3YubrJjzgLYZUAXPXcWz3yfj6 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-10-21_02,2026-10-19_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 phishscore=0 bulkscore=0 adultscore=0 malwarescore=0 clxscore=1015 spamscore=0 impostorscore=0 lowpriorityscore=0 suspectscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2610190000 definitions=main-2610210030 On 19.10.26 15:22, Haoran Wang wrote: > afiucv_netdev_event() traverses iucv_sk_list.head with sk_for_each() > without holding iucv_sk_list.lock: > > /* net/iucv/af_iucv.c:2218 */ > sk_for_each(sk, &iucv_sk_list.head) { > iucv = iucv_sk(sk); > if ((iucv->hs_dev == event_dev) && > (sk->sk_state == IUCV_CONNECTED)) { > if (event == NETDEV_GOING_DOWN) > iucv_send_ctrl(sk, AF_IUCV_FLAG_FIN); > sk->sk_state = IUCV_DISCONN; > sk->sk_state_change(sk); > } > } > Hello Haoran Wang, thank you for your contribution. I think the issue you are fixing is the same that Nagamani already sent a fix for [1]. We are currently working on hardening the basic socket locking mechanism in af_iucv [2], and I asked Nagamani to hold off until that work is done. So I think this issue is already being worked on (please correct me, if I'm wrong). Feel free to comment on Nagamani's proposal, as you have an understanding of the issue. Kind regards Alexandra Link: https://lore.kernel.org/netdev/20260803182053.2355882-1-nagamani@linux.ibm.com/ [1] Link: https://lore.kernel.org/netdev/20260724222917.134769-1-hexlabsecurity@proton.me/ [2]