From patchwork Thu Jan 18 04:32:10 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wen Gu X-Patchwork-Id: 13522360 X-Patchwork-Delegate: kuba@kernel.org Received: from out30-99.freemail.mail.aliyun.com (out30-99.freemail.mail.aliyun.com [115.124.30.99]) (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 43ACCA41; Thu, 18 Jan 2024 04:32:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.99 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705552359; cv=none; b=fnR8OXaS4j3Ta3F9qD4/mKXNWh+xmY++3UaO9E8D8h2i289RKH33AFY5ot5j2za4GugDUckW5BbYgcLjAKzUHNDPwoCGb/GAZ0Nhp6BGODCgXd8l71XAfC9swF1e/fm2DhwCPBUX9ZFlAtlycHiUPvdZPBtu3ZUZo78TOpNjEfM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705552359; c=relaxed/simple; bh=L2R//kp2TZYjI88M/hmHTS7NxUGrsSRm1/69OpIek1A=; h=X-Alimail-AntiSpam:Received:From:To:Cc:Subject:Date:Message-Id: X-Mailer:MIME-Version:Content-Transfer-Encoding; b=RbN84TzfTM0X/8M118BdpXJ9QiQBqQNAxctlsR6mjDke422HTR//+KBAWl0ZMWOoq9InJULKDvSDmkVe1ky68mLmeVrctJGVomAUXTPj5BaCvzGyI3cU4tbWTnb0s+2AM7LrVpovM7GAnInhFVdn0+Ew16CJ5u5WCPG9101mmNw= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; arc=none smtp.client-ip=115.124.30.99 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R201e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018045176;MF=guwen@linux.alibaba.com;NM=1;PH=DS;RN=13;SR=0;TI=SMTPD_---0W-rRrfZ_1705552330; Received: from localhost(mailfrom:guwen@linux.alibaba.com fp:SMTPD_---0W-rRrfZ_1705552330) by smtp.aliyun-inc.com; Thu, 18 Jan 2024 12:32:29 +0800 From: Wen Gu To: wenjia@linux.ibm.com, 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, guwen@linux.alibaba.com, ubraun@linux.ibm.com, linux-s390@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH net v2] net/smc: fix illegal rmb_desc access in SMC-D connection dump Date: Thu, 18 Jan 2024 12:32:10 +0800 Message-Id: <20240118043210.47618-1-guwen@linux.alibaba.com> X-Mailer: git-send-email 2.32.0.3.g01195cf9f Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Patchwork-Delegate: kuba@kernel.org A crash was found when dumping SMC-D connections. It can be reproduced by following steps: - run nginx/wrk test: smc_run nginx smc_run wrk -t 16 -c 1000 -d -H 'Connection: Close' - continuously dump SMC-D connections in parallel: watch -n 1 'smcss -D' BUG: kernel NULL pointer dereference, address: 0000000000000030 CPU: 2 PID: 7204 Comm: smcss Kdump: loaded Tainted: G E 6.7.0+ #55 RIP: 0010:__smc_diag_dump.constprop.0+0x5e5/0x620 [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+0x5e5/0x620 [smc_diag] ? __kmalloc_node_track_caller+0x35d/0x430 ? __alloc_skb+0x77/0x170 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+0x1f8/0x420 __sock_sendmsg+0xb0/0xc0 ____sys_sendmsg+0x24e/0x300 ? copy_msghdr_from_user+0x62/0x80 ___sys_sendmsg+0x7c/0xd0 ? __do_fault+0x34/0x160 ? do_read_fault+0x5f/0x100 ? do_fault+0xb0/0x110 ? __handle_mm_fault+0x2b0/0x6c0 __sys_sendmsg+0x4d/0x80 do_syscall_64+0x69/0x180 entry_SYSCALL_64_after_hwframe+0x6e/0x76 It is possible that the connection is in process of being established when we dump it. Assumed that the connection has been registered in a link group by smc_conn_create() but the rmb_desc has not yet been initialized by smc_buf_create(), thus causing the illegal access to conn->rmb_desc. So fix it by checking before dump. Fixes: 4b1b7d3b30a6 ("net/smc: add SMC-D diag support") Signed-off-by: Wen Gu Reviewed-by: Dust Li Reviewed-by: Wenjia Zhang --- v2->v1: corrected the commit in Fixes tag. (https://lore.kernel.org/netdev/20240117122749.63785-1-guwen@linux.alibaba.com/) net/smc/smc_diag.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/smc/smc_diag.c b/net/smc/smc_diag.c index 52f7c4f1e767..5a33908015f3 100644 --- a/net/smc/smc_diag.c +++ b/net/smc/smc_diag.c @@ -164,7 +164,7 @@ static int __smc_diag_dump(struct sock *sk, struct sk_buff *skb, } if (smc_conn_lgr_valid(&smc->conn) && smc->conn.lgr->is_smcd && (req->diag_ext & (1 << (SMC_DIAG_DMBINFO - 1))) && - !list_empty(&smc->conn.lgr->list)) { + !list_empty(&smc->conn.lgr->list) && smc->conn.rmb_desc) { struct smc_connection *conn = &smc->conn; struct smcd_diag_dmbinfo dinfo; struct smcd_dev *smcd = conn->lgr->smcd;