From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 429B5C2D0A8 for ; Sat, 26 Sep 2020 16:56:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D9D5A2071E for ; Sat, 26 Sep 2020 16:56:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="CxiwS6oP" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729907AbgIZQ4g (ORCPT ); Sat, 26 Sep 2020 12:56:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44800 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729763AbgIZQ4g (ORCPT ); Sat, 26 Sep 2020 12:56:36 -0400 Received: from mail-pl1-x644.google.com (mail-pl1-x644.google.com [IPv6:2607:f8b0:4864:20::644]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7A6F2C0613D3 for ; Sat, 26 Sep 2020 09:56:36 -0700 (PDT) Received: by mail-pl1-x644.google.com with SMTP id e4so1010292pln.10 for ; Sat, 26 Sep 2020 09:56:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id; bh=SVaJEVx3uY1TIDW2WVtd8VWUc74/BP701w9CmWsP2ok=; b=CxiwS6oP1IEB7r6bdBr1EaoR1GNhHMPSER8WzM0pd7a/qZU1XucYgI9FiVHsnwdaGY 9hHs3vswi2h8ER5CDxaKDT7aIXmw6dx6bVx5l/lDVwHUyX2hDcD/fkbvhOn1zeqMYvp7 iXI7DRSHufFp2SLp03tAYIiEp/X1/GrLcgw+opDyZqE4IsF46LPY1PvANrdKpgZRQ0Rm mT9R7Mrh7bIjt8Y49ERHl7qrtsjoOAYDUC1eEw5bbHUKgQX0k0K+P1il+QqPB4Z6F/MG 4Qco9Rk9WT9mOtVzPHP2jbdq10F6wPXoe/MWUDGJts3nPKdWhK9eBVsQcrBsX+/xP1At L3/w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=SVaJEVx3uY1TIDW2WVtd8VWUc74/BP701w9CmWsP2ok=; b=fApe4amCDfnFSX/LM22hkTrRT3v8fqRGEEgInNqRCSmM9xysn0AhaPYV6LJSOhRSzA vCWYW2VoiV8NdTy403sl2jD9fzX4uSQo6/ensI5sN9LCzXU7cM9i6FLWsnzsqDPvX0H4 7HRqzdsvva40sMYkqjiErS15MPDlMePDOjKmv7IzZ88ocQ6PqU5H6Gqi5SZZqejIbogd sAJlx9J9ioMN1c9+6pmw2lhNpuj8RPC+emiJfk+VbJiiQNNXIwZ/4mCUUB3v/oGaaVzl VBsSyjFTptpyASpzqwQ2ZLS9/m+BKmnQtsqTEhXTatSx+UrG3Wo5z0dqJUpeeHl9XHqr 32WA== X-Gm-Message-State: AOAM533rKpBmkY5vpQ3aWuJUmRIRTaNK9OyrbJ4cGQ01OD+wvKNrbnZf qMsxNhdwJg3yEi+3Lv4oxbNY X-Google-Smtp-Source: ABdhPJzNC6LFuvvQ5gUUw3Dq9W9gpSzB7SSeCXmcxmo9cmtpNJPtro32GrVENIJbYn7rZ5aLySsRQQ== X-Received: by 2002:a17:90a:2a88:: with SMTP id j8mr1192410pjd.35.1601139395744; Sat, 26 Sep 2020 09:56:35 -0700 (PDT) Received: from Mani-XPS-13-9360.localdomain ([2409:4072:20d:ee7b:91b:1587:faf3:6b2b]) by smtp.gmail.com with ESMTPSA id kf10sm2220996pjb.2.2020.09.26.09.56.30 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 26 Sep 2020 09:56:34 -0700 (PDT) From: Manivannan Sadhasivam To: davem@davemloft.net, kuba@kernel.org Cc: bjorn.andersson@linaro.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, sboyd@kernel.org, Manivannan Sadhasivam Subject: [PATCH] net: qrtr: ns: Protect radix_tree_deref_slot() using rcu read locks Date: Sat, 26 Sep 2020 22:26:25 +0530 Message-Id: <20200926165625.11660-1-manivannan.sadhasivam@linaro.org> X-Mailer: git-send-email 2.17.1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The rcu read locks are needed to avoid potential race condition while dereferencing radix tree from multiple threads. The issue was identified by syzbot. Below is the crash report: ============================= WARNING: suspicious RCU usage 5.7.0-syzkaller #0 Not tainted ----------------------------- include/linux/radix-tree.h:176 suspicious rcu_dereference_check() usage! other info that might help us debug this: rcu_scheduler_active = 2, debug_locks = 1 2 locks held by kworker/u4:1/21: #0: ffff88821b097938 ((wq_completion)qrtr_ns_handler){+.+.}-{0:0}, at: spin_unlock_irq include/linux/spinlock.h:403 [inline] #0: ffff88821b097938 ((wq_completion)qrtr_ns_handler){+.+.}-{0:0}, at: process_one_work+0x6df/0xfd0 kernel/workqueue.c:2241 #1: ffffc90000dd7d80 ((work_completion)(&qrtr_ns.work)){+.+.}-{0:0}, at: process_one_work+0x71e/0xfd0 kernel/workqueue.c:2243 stack backtrace: CPU: 0 PID: 21 Comm: kworker/u4:1 Not tainted 5.7.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Workqueue: qrtr_ns_handler qrtr_ns_worker Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1e9/0x30e lib/dump_stack.c:118 radix_tree_deref_slot include/linux/radix-tree.h:176 [inline] ctrl_cmd_new_lookup net/qrtr/ns.c:558 [inline] qrtr_ns_worker+0x2aff/0x4500 net/qrtr/ns.c:674 process_one_work+0x76e/0xfd0 kernel/workqueue.c:2268 worker_thread+0xa7f/0x1450 kernel/workqueue.c:2414 kthread+0x353/0x380 kernel/kthread.c:268 Fixes: 0c2204a4ad71 ("net: qrtr: Migrate nameservice to kernel from userspace") Reported-and-tested-by: syzbot+0f84f6eed90503da72fc@syzkaller.appspotmail.com Signed-off-by: Manivannan Sadhasivam --- net/qrtr/ns.c | 34 +++++++++++++++++++++++++--------- 1 file changed, 25 insertions(+), 9 deletions(-) diff --git a/net/qrtr/ns.c b/net/qrtr/ns.c index d8252fdab851..934999b56d60 100644 --- a/net/qrtr/ns.c +++ b/net/qrtr/ns.c @@ -193,12 +193,13 @@ static int announce_servers(struct sockaddr_qrtr *sq) struct qrtr_server *srv; struct qrtr_node *node; void __rcu **slot; - int ret; + int ret = 0; node = node_get(qrtr_ns.local_node); if (!node) return 0; + rcu_read_lock(); /* Announce the list of servers registered in this node */ radix_tree_for_each_slot(slot, &node->servers, &iter, 0) { srv = radix_tree_deref_slot(slot); @@ -206,11 +207,14 @@ static int announce_servers(struct sockaddr_qrtr *sq) ret = service_announce_new(sq, srv); if (ret < 0) { pr_err("failed to announce new service\n"); - return ret; + goto err_out; } } - return 0; +err_out: + rcu_read_unlock(); + + return ret; } static struct qrtr_server *server_add(unsigned int service, @@ -335,7 +339,7 @@ static int ctrl_cmd_bye(struct sockaddr_qrtr *from) struct qrtr_node *node; void __rcu **slot; struct kvec iv; - int ret; + int ret = 0; iv.iov_base = &pkt; iv.iov_len = sizeof(pkt); @@ -344,11 +348,13 @@ static int ctrl_cmd_bye(struct sockaddr_qrtr *from) if (!node) return 0; + rcu_read_lock(); /* Advertise removal of this client to all servers of remote node */ radix_tree_for_each_slot(slot, &node->servers, &iter, 0) { srv = radix_tree_deref_slot(slot); server_del(node, srv->port); } + rcu_read_unlock(); /* Advertise the removal of this client to all local servers */ local_node = node_get(qrtr_ns.local_node); @@ -359,6 +365,7 @@ static int ctrl_cmd_bye(struct sockaddr_qrtr *from) pkt.cmd = cpu_to_le32(QRTR_TYPE_BYE); pkt.client.node = cpu_to_le32(from->sq_node); + rcu_read_lock(); radix_tree_for_each_slot(slot, &local_node->servers, &iter, 0) { srv = radix_tree_deref_slot(slot); @@ -372,11 +379,14 @@ static int ctrl_cmd_bye(struct sockaddr_qrtr *from) ret = kernel_sendmsg(qrtr_ns.sock, &msg, &iv, 1, sizeof(pkt)); if (ret < 0) { pr_err("failed to send bye cmd\n"); - return ret; + goto err_out; } } - return 0; +err_out: + rcu_read_unlock(); + + return ret; } static int ctrl_cmd_del_client(struct sockaddr_qrtr *from, @@ -394,7 +404,7 @@ static int ctrl_cmd_del_client(struct sockaddr_qrtr *from, struct list_head *li; void __rcu **slot; struct kvec iv; - int ret; + int ret = 0; iv.iov_base = &pkt; iv.iov_len = sizeof(pkt); @@ -434,6 +444,7 @@ static int ctrl_cmd_del_client(struct sockaddr_qrtr *from, pkt.client.node = cpu_to_le32(node_id); pkt.client.port = cpu_to_le32(port); + rcu_read_lock(); radix_tree_for_each_slot(slot, &local_node->servers, &iter, 0) { srv = radix_tree_deref_slot(slot); @@ -447,11 +458,14 @@ static int ctrl_cmd_del_client(struct sockaddr_qrtr *from, ret = kernel_sendmsg(qrtr_ns.sock, &msg, &iv, 1, sizeof(pkt)); if (ret < 0) { pr_err("failed to send del client cmd\n"); - return ret; + goto err_out; } } - return 0; +err_out: + rcu_read_unlock(); + + return ret; } static int ctrl_cmd_new_server(struct sockaddr_qrtr *from, @@ -554,6 +568,7 @@ static int ctrl_cmd_new_lookup(struct sockaddr_qrtr *from, filter.service = service; filter.instance = instance; + rcu_read_lock(); radix_tree_for_each_slot(node_slot, &nodes, &node_iter, 0) { node = radix_tree_deref_slot(node_slot); @@ -568,6 +583,7 @@ static int ctrl_cmd_new_lookup(struct sockaddr_qrtr *from, lookup_notify(from, srv, true); } } + rcu_read_unlock(); /* Empty notification, to indicate end of listing */ lookup_notify(from, NULL, true); -- 2.17.1