From patchwork Mon May 31 13:13:53 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 451029 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=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, 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 A154FC47080 for ; Mon, 31 May 2021 14:21:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 86BD6613D7 for ; Mon, 31 May 2021 14:21:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231376AbhEaOWq (ORCPT ); Mon, 31 May 2021 10:22:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:43916 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233475AbhEaOTI (ORCPT ); Mon, 31 May 2021 10:19:08 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 0EB19619AC; Mon, 31 May 2021 13:44:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1622468661; bh=83hgqXB9c02SMS7hFiF02T7zD6l8Ptsb4vG8PVf3AIE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=m1ZEvdQnlpAm2aiSSa464oOu0hSHr0F66A2yGI+J1UDbHSqwBYBQhqS344bjJqcRG fWcrTRa28Q+lFl16KK7FA7svvT7wiS2sB1Ku9fTt7WAVAfJgg7VIp9Pv7cVCfwXm6S kkjYJWuOYxhE3JNM+TyZ/iZ59viWdJ9XM6eA9AT8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Shuang Li , Xin Long , Jon Maloy , "David S. Miller" Subject: [PATCH 5.4 076/177] tipc: wait and exit until all work queues are done Date: Mon, 31 May 2021 15:13:53 +0200 Message-Id: <20210531130650.520391414@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210531130647.887605866@linuxfoundation.org> References: <20210531130647.887605866@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Xin Long commit 04c26faa51d1e2fe71cf13c45791f5174c37f986 upstream. On some host, a crash could be triggered simply by repeating these commands several times: # modprobe tipc # tipc bearer enable media udp name UDP1 localip 127.0.0.1 # rmmod tipc [] BUG: unable to handle kernel paging request at ffffffffc096bb00 [] Workqueue: events 0xffffffffc096bb00 [] Call Trace: [] ? process_one_work+0x1a7/0x360 [] ? worker_thread+0x30/0x390 [] ? create_worker+0x1a0/0x1a0 [] ? kthread+0x116/0x130 [] ? kthread_flush_work_fn+0x10/0x10 [] ? ret_from_fork+0x35/0x40 When removing the TIPC module, the UDP tunnel sock will be delayed to release in a work queue as sock_release() can't be done in rtnl_lock(). If the work queue is schedule to run after the TIPC module is removed, kernel will crash as the work queue function cleanup_beareri() code no longer exists when trying to invoke it. To fix it, this patch introduce a member wq_count in tipc_net to track the numbers of work queues in schedule, and wait and exit until all work queues are done in tipc_exit_net(). Fixes: d0f91938bede ("tipc: add ip/udp media type") Reported-by: Shuang Li Signed-off-by: Xin Long Acked-by: Jon Maloy Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman --- net/tipc/core.c | 3 +++ net/tipc/core.h | 2 ++ net/tipc/udp_media.c | 2 ++ 3 files changed, 7 insertions(+) --- a/net/tipc/core.c +++ b/net/tipc/core.c @@ -107,6 +107,9 @@ static void __net_exit tipc_exit_net(str tipc_bcast_stop(net); tipc_nametbl_stop(net); tipc_sk_rht_destroy(net); + + while (atomic_read(&tn->wq_count)) + cond_resched(); } static struct pernet_operations tipc_net_ops = { --- a/net/tipc/core.h +++ b/net/tipc/core.h @@ -143,6 +143,8 @@ struct tipc_net { /* Work item for net finalize */ struct tipc_net_work final_work; + /* The numbers of work queues in schedule */ + atomic_t wq_count; }; static inline struct tipc_net *tipc_net(struct net *net) --- a/net/tipc/udp_media.c +++ b/net/tipc/udp_media.c @@ -802,6 +802,7 @@ static void cleanup_bearer(struct work_s kfree_rcu(rcast, rcu); } + atomic_dec(&tipc_net(sock_net(ub->ubsock->sk))->wq_count); dst_cache_destroy(&ub->rcast.dst_cache); udp_tunnel_sock_release(ub->ubsock); synchronize_net(); @@ -822,6 +823,7 @@ static void tipc_udp_disable(struct tipc RCU_INIT_POINTER(ub->bearer, NULL); /* sock_release need to be done outside of rtnl lock */ + atomic_inc(&tipc_net(sock_net(ub->ubsock->sk))->wq_count); INIT_WORK(&ub->work, cleanup_bearer); schedule_work(&ub->work); }