From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0a-001b2d01.pphosted.com (mx0a-001b2d01.pphosted.com [148.163.156.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7045118623; Wed, 3 Jan 2024 09:33:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.ibm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ibm.com header.i=@ibm.com header.b="WIo7r1gT" Received: from pps.filterd (m0353726.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.17.1.19/8.17.1.19) with ESMTP id 4038tSe4011438; Wed, 3 Jan 2024 09:33:32 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=message-id : date : subject : to : cc : references : from : in-reply-to : content-type : content-transfer-encoding : mime-version; s=pp1; bh=u7vbuh9S5hS2XPx/rfCPO3a+vWqn15NPQT6wBmi/7FQ=; b=WIo7r1gTRRIMFeD2rt75K88j+11PYNW4c46Cd7XOHPEgBoBTR5v7PceCxYVRiV6iQ5Qr nvVqYWTi/yBcdkVSj+I6UqJ01pKT5IGJrPGHbkzhttPtucPVMCZCrarX+kYL7LeePWL7 npzunjYIUGsZ6LecCBqV01PBEQ2PXb1gBzrYZW7gOxUe0hcbig7Ykpw0SFybnTujFpsf tNilEaKlQsj0RJzX9PslsFOI3aoKvxa1WEU0VkNOAji5Nw0K4R4rl3my/IvSzo7L8JpI cVZjfwMrFeZVXlysNH5TFop7E7w2Fb8V7kM/4DZDeEgu5NKOfz5ZtyV06EvBcjBGONOk ug== Received: from pps.reinject (localhost [127.0.0.1]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3vd4821xdm-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 03 Jan 2024 09:33:31 +0000 Received: from m0353726.ppops.net (m0353726.ppops.net [127.0.0.1]) by pps.reinject (8.17.1.5/8.17.1.5) with ESMTP id 4038tWmc011861; Wed, 3 Jan 2024 09:33:31 GMT Received: from ppma23.wdc07v.mail.ibm.com (5d.69.3da9.ip4.static.sl-reverse.com [169.61.105.93]) by mx0a-001b2d01.pphosted.com (PPS) with ESMTPS id 3vd4821xce-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 03 Jan 2024 09:33:30 +0000 Received: from pps.filterd (ppma23.wdc07v.mail.ibm.com [127.0.0.1]) by ppma23.wdc07v.mail.ibm.com (8.17.1.19/8.17.1.19) with ESMTP id 4036xkKh019345; Wed, 3 Jan 2024 09:33:29 GMT Received: from smtprelay01.wdc07v.mail.ibm.com ([172.16.1.68]) by ppma23.wdc07v.mail.ibm.com (PPS) with ESMTPS id 3vc30sha9m-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Wed, 03 Jan 2024 09:33:29 +0000 Received: from smtpav06.wdc07v.mail.ibm.com (smtpav06.wdc07v.mail.ibm.com [10.39.53.233]) by smtprelay01.wdc07v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 4039XT9N31326524 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Wed, 3 Jan 2024 09:33:29 GMT Received: from smtpav06.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 0D0D45803F; Wed, 3 Jan 2024 09:33:29 +0000 (GMT) Received: from smtpav06.wdc07v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 8759A58060; Wed, 3 Jan 2024 09:33:26 +0000 (GMT) Received: from [9.171.87.115] (unknown [9.171.87.115]) by smtpav06.wdc07v.mail.ibm.com (Postfix) with ESMTP; Wed, 3 Jan 2024 09:33:26 +0000 (GMT) Message-ID: <0a501939-3361-428e-97c4-6f041a9ec1f9@linux.ibm.com> Date: Wed, 3 Jan 2024 10:33:25 +0100 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net] net/smc: fix invalid link access in dumping SMC-R connections To: Wen Gu , jaka@linux.ibm.com, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com Cc: alibuda@linux.alibaba.com, tonylu@linux.alibaba.com, ubraun@linux.vnet.ibm.com, linux-s390@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <1703662835-53416-1-git-send-email-guwen@linux.alibaba.com> Content-Language: en-GB From: Wenjia Zhang In-Reply-To: <1703662835-53416-1-git-send-email-guwen@linux.alibaba.com> Content-Type: text/plain; charset=UTF-8; format=flowed X-TM-AS-GCONF: 00 X-Proofpoint-GUID: KJYL8MCvw3wW-NrXsAMilm66u5tPB0Tw X-Proofpoint-ORIG-GUID: fus5OwQNizTGTLMwpikTYmnAsFDHQrKn Content-Transfer-Encoding: 7bit X-Proofpoint-UnRewURL: 0 URL was un-rewritten Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.272,Aquarius:18.0.997,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2024-01-03_04,2024-01-02_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 phishscore=0 lowpriorityscore=0 clxscore=1011 mlxlogscore=784 malwarescore=0 bulkscore=0 priorityscore=1501 impostorscore=0 spamscore=0 mlxscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2311290000 definitions=main-2401030078 On 27.12.23 08:40, Wen Gu wrote: > A crash was found when dumping SMC-R connections. It can be reproduced > by following steps: > > - environment: two RNICs on both sides. > - run SMC-R between two sides, now a SMC_LGR_SYMMETRIC type link group > will be created. > - set the first RNIC down on either side and link group will turn to > SMC_LGR_ASYMMETRIC_LOCAL then. > - run 'smcss -R' and the crash will be triggered. > > BUG: kernel NULL pointer dereference, address: 0000000000000010 > #PF: supervisor read access in kernel mode > #PF: error_code(0x0000) - not-present page > PGD 8000000101fdd067 P4D 8000000101fdd067 PUD 10ce46067 PMD 0 > Oops: 0000 [#1] PREEMPT SMP PTI > CPU: 3 PID: 1810 Comm: smcss Kdump: loaded Tainted: G W E 6.7.0-rc6+ #51 > RIP: 0010:__smc_diag_dump.constprop.0+0x36e/0x620 [smc_diag] > Call Trace: > > ? __die+0x24/0x70 > ? page_fault_oops+0x66/0x150 > ? exc_page_fault+0x69/0x140 > ? asm_exc_page_fault+0x26/0x30 > ? __smc_diag_dump.constprop.0+0x36e/0x620 [smc_diag] > smc_diag_dump_proto+0xd0/0xf0 [smc_diag] > smc_diag_dump+0x26/0x60 [smc_diag] > netlink_dump+0x19f/0x320 > __netlink_dump_start+0x1dc/0x300 > smc_diag_handler_dump+0x6a/0x80 [smc_diag] > ? __pfx_smc_diag_dump+0x10/0x10 [smc_diag] > sock_diag_rcv_msg+0x121/0x140 > ? __pfx_sock_diag_rcv_msg+0x10/0x10 > netlink_rcv_skb+0x5a/0x110 > sock_diag_rcv+0x28/0x40 > netlink_unicast+0x22a/0x330 > netlink_sendmsg+0x240/0x4a0 > __sock_sendmsg+0xb0/0xc0 > ____sys_sendmsg+0x24e/0x300 > ? copy_msghdr_from_user+0x62/0x80 > ___sys_sendmsg+0x7c/0xd0 > ? __do_fault+0x34/0x1a0 > ? do_read_fault+0x5f/0x100 > ? do_fault+0xb0/0x110 > __sys_sendmsg+0x4d/0x80 > do_syscall_64+0x45/0xf0 > entry_SYSCALL_64_after_hwframe+0x6e/0x76 > > When the first RNIC is set down, the lgr->lnk[0] will be cleared and an > asymmetric link will be allocated in lgr->link[SMC_LINKS_PER_LGR_MAX - 1] > by smc_llc_alloc_alt_link(). Then when we try to dump SMC-R connections > in __smc_diag_dump(), the invalid lgr->lnk[0] will be accessed, resulting > in this issue. So fix it by accessing the right link. > > Fixes: f16a7dd5cf27 ("smc: netlink interface for SMC sockets") > Reported-by: henaumars > Closes: https://bugzilla.openanolis.cn/show_bug.cgi?id=7616 > Signed-off-by: Wen Gu That is really good catch and good description! Thank you, Wen Gu, for fixing it! Reviewed-and-tested-by: Wenjia Zhang