From patchwork Tue Jan 3 11:12:46 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ying Hsu X-Patchwork-Id: 13087385 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 04CA4C46467 for ; Tue, 3 Jan 2023 11:12:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237314AbjACLM4 (ORCPT ); Tue, 3 Jan 2023 06:12:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51228 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237203AbjACLMy (ORCPT ); Tue, 3 Jan 2023 06:12:54 -0500 Received: from mail-pf1-x432.google.com (mail-pf1-x432.google.com [IPv6:2607:f8b0:4864:20::432]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DB789766C for ; Tue, 3 Jan 2023 03:12:53 -0800 (PST) Received: by mail-pf1-x432.google.com with SMTP id k19so12600547pfg.11 for ; Tue, 03 Jan 2023 03:12:53 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=zV1fKa5X+fJOsn4eYW6XzdvCXBtHTAKTAI3MhIsCmO4=; b=SGzEEFR+GoTUobK0+7F9Kmyzh1nbOZpcTxLxEGTAPc5W/w0fxNKhwo1nh6zq/xemqV ZGZ88mIku/BfHh17O2Wgn6emQ2eBVdJ7cGebWAzFiwJ/o4ao/6HOwZOhOU1B0b+ZVck9 37oxkqjsaL9GRNItnkGyo48OeswFAI+ihuNgg= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=zV1fKa5X+fJOsn4eYW6XzdvCXBtHTAKTAI3MhIsCmO4=; b=gPEeTCif3MHfRXCZDOxnWpr8I4uNPoOv3g4/O4hhwuPSbFaASZxLayquHVLJmLr3AG 5j2d2Hts0Fro2dmo6Bx6vaWivxnkTGFIqHktXzhHoreYyl1i/ctCxQRyqQYhzCm/PSAF CrWd9Nh9nkyNswQz2CX3ZnMMYgF9zd+4rXxJK4Y16z8B+f8gbKzrZDloD1715ISdlRNf EbYGG4WBtKCFjnw+HljjhO5xtnm5VXM4dxpPZwRT0qHcufFaS+GVQNFLqo8mSiTJ5/tt vvYqXSc6T8HV2emaXAyHTqjMGFjaeNUTpXh7s3wztZjMRQjY/RoSNlgd8R/jESUIzSKl prnw== X-Gm-Message-State: AFqh2koMLd51+zESguof/6erq9kQQuliTCYHF7tKXcyk/AgOo05Rt3Ry qANGGbogSzCZOzJtOeTEDmGYSQA91rfomrOn X-Google-Smtp-Source: AMrXdXvsFr/twvKjLq5UpMvFhw7+7+tn3FPr9WEIq3WQJd/RgAMu6NwsTl3OZzqe1dl8lc45CCUSPw== X-Received: by 2002:a05:6a00:84c:b0:581:1ee0:75a with SMTP id q12-20020a056a00084c00b005811ee0075amr36871808pfk.32.1672744373075; Tue, 03 Jan 2023 03:12:53 -0800 (PST) Received: from localhost (21.160.199.104.bc.googleusercontent.com. [104.199.160.21]) by smtp.gmail.com with UTF8SMTPSA id k187-20020a6284c4000000b005769b23260fsm20829792pfd.18.2023.01.03.03.12.50 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 03 Jan 2023 03:12:52 -0800 (PST) From: Ying Hsu To: linux-bluetooth@vger.kernel.org Cc: chromeos-bluetooth-upstreaming@chromium.org, Ying Hsu , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Johan Hedberg , Luiz Augusto von Dentz , Marcel Holtmann , Paolo Abeni , linux-kernel@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH] Bluetooth: Fix possible deadlock in rfcomm_sk_state_change Date: Tue, 3 Jan 2023 11:12:46 +0000 Message-Id: <20230103111221.1.I1f29bb547a03e9adfe2e6754212f9d14a2e39c4b@changeid> X-Mailer: git-send-email 2.39.0.314.g84b9a713c41-goog MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-bluetooth@vger.kernel.org There's a possible deadlock when two processes are connecting and closing concurrently: + CPU0: __rfcomm_dlc_close locks rfcomm and then calls rfcomm_sk_state_change which locks the sock. + CPU1: rfcomm_sock_connect locks the socket and then calls rfcomm_dlc_open which locks rfcomm. Here's the call trace: -> #2 (&d->lock){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock0x12f/0x1360 kernel/locking/mutex.c:747 __rfcomm_dlc_close+0x15d/0x890 net/bluetooth/rfcomm/core.c:487 rfcomm_dlc_close+1e9/0x240 net/bluetooth/rfcomm/core.c:520 __rfcomm_sock_close+0x13c/0x250 net/bluetooth/rfcomm/sock.c:220 rfcomm_sock_shutdown+0xd8/0x230 net/bluetooth/rfcomm/sock.c:907 rfcomm_sock_release+0x68/0x140 net/bluetooth/rfcomm/sock.c:928 __sock_release+0xcd/0x280 net/socket.c:650 sock_close+0x1c/0x20 net/socket.c:1365 __fput+0x27c/0xa90 fs/file_table.c:320 task_work_run+0x16f/0x270 kernel/task_work.c:179 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0xaa8/0x2950 kernel/exit.c:867 do_group_exit+0xd4/0x2a0 kernel/exit.c:1012 get_signal+0x21c3/0x2450 kernel/signal.c:2859 arch_do_signal_or_restart+0x79/0x5c0 arch/x86/kernel/signal.c:306 exit_to_user_mode_loop kernel/entry/common.c:168 [inline] exit_to_user_mode_prepare+0x15f/0x250 kernel/entry/common.c:203 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline] syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:296 do_syscall_64+0x46/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #1 (rfcomm_mutex){+.+.}-{3:3}: __mutex_lock_common kernel/locking/mutex.c:603 [inline] __mutex_lock+0x12f/0x1360 kernel/locking/mutex.c:747 rfcomm_dlc_open+0x93/0xa80 net/bluetooth/rfcomm/core.c:425 rfcomm_sock_connect+0x329/0x450 net/bluetooth/rfcomm/sock.c:413 __sys_connect_file+0x153/0x1a0 net/socket.c:1976 __sys_connect+0x165/0x1a0 net/socket.c:1993 __do_sys_connect net/socket.c:2003 [inline] __se_sys_connect net/socket.c:2000 [inline] __x64_sys_connect+0x73/0xb0 net/socket.c:2000 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd -> #0 (sk_lock-AF_BLUETOOTH-BTPROTO_RFCOMM){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3097 [inline] check_prevs_add kernel/locking/lockdep.c:3216 [inline] validate_chain kernel/locking/lockdep.c:3831 [inline] __lock_acquire+0x2a43/0x56d0 kernel/locking/lockdep.c:5055 lock_acquire kernel/locking/lockdep.c:5668 [inline] lock_acquire+0x1e3/0x630 kernel/locking/lockdep.c:5633 lock_sock_nested+0x3a/0xf0 net/core/sock.c:3470 lock_sock include/net/sock.h:1725 [inline] rfcomm_sk_state_change+0x6d/0x3a0 net/bluetooth/rfcomm/sock.c:73 __rfcomm_dlc_close+0x1b1/0x890 net/bluetooth/rfcomm/core.c:489 rfcomm_dlc_close+0x1e9/0x240 net/bluetooth/rfcomm/core.c:520 __rfcomm_sock_close+0x13c/0x250 net/bluetooth/rfcomm/sock.c:220 rfcomm_sock_shutdown+0xd8/0x230 net/bluetooth/rfcomm/sock.c:907 rfcomm_sock_release+0x68/0x140 net/bluetooth/rfcomm/sock.c:928 __sock_release+0xcd/0x280 net/socket.c:650 sock_close+0x1c/0x20 net/socket.c:1365 __fput+0x27c/0xa90 fs/file_table.c:320 task_work_run+0x16f/0x270 kernel/task_work.c:179 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0xaa8/0x2950 kernel/exit.c:867 do_group_exit+0xd4/0x2a0 kernel/exit.c:1012 get_signal+0x21c3/0x2450 kernel/signal.c:2859 arch_do_signal_or_restart+0x79/0x5c0 arch/x86/kernel/signal.c:306 exit_to_user_mode_loop kernel/entry/common.c:168 [inline] exit_to_user_mode_prepare+0x15f/0x250 kernel/entry/common.c:203 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline] syscall_exit_to_user_mode+0x1d/0x50 kernel/entry/common.c:296 do_syscall_64+0x46/0xb0 arch/x86/entry/common.c:86 entry_SYSCALL_64_after_hwframe+0x63/0xcd Signed-off-by: Ying Hsu Reviewed-by: Saeed Mahameed --- This commit has been tested with a C reproducer on qemu-x86_64. net/bluetooth/rfcomm/sock.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c index 21e24da4847f..29f9a88a3dc8 100644 --- a/net/bluetooth/rfcomm/sock.c +++ b/net/bluetooth/rfcomm/sock.c @@ -410,8 +410,10 @@ static int rfcomm_sock_connect(struct socket *sock, struct sockaddr *addr, int a d->sec_level = rfcomm_pi(sk)->sec_level; d->role_switch = rfcomm_pi(sk)->role_switch; + release_sock(sk); err = rfcomm_dlc_open(d, &rfcomm_pi(sk)->src, &sa->rc_bdaddr, sa->rc_channel); + lock_sock(sk); if (!err) err = bt_sock_wait_state(sk, BT_CONNECTED, sock_sndtimeo(sk, flags & O_NONBLOCK));