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Tue, 18 Apr 2023 12:49:56 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 93ECAC433D2; Tue, 18 Apr 2023 12:49:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1681822195; bh=gDlxUZ1mPVhgwJcnDzU2x4Mp65YZFnSvOCftdKJLIog=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=eB8l/RcYjCaeaNvQ0mw2qlZRQWgyzeG+7jzf7sr1adSNERoCjQSrCivZdWi32rkx+ 21tsolndrxHPknp5OnOBeFiFq9Ee6iRcb5UlFL2wCgQ5I9ocJZHCwv9mBWvcwh/MnE HBk6V3aPsHJ4DWRmW3/0IJzhLwmR48nCmxs5BAaA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Luiz Augusto von Dentz , Sasha Levin Subject: [PATCH 6.2 058/139] Bluetooth: SCO: Fix possible circular locking dependency sco_sock_getsockopt Date: Tue, 18 Apr 2023 14:22:03 +0200 Message-Id: <20230418120315.943440248@linuxfoundation.org> X-Mailer: git-send-email 2.40.0 In-Reply-To: <20230418120313.725598495@linuxfoundation.org> References: <20230418120313.725598495@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Luiz Augusto von Dentz [ Upstream commit 975abc0c90fc485ff9b4a6afa475c3b1398d5d47 ] This attempts to fix the following trace: ====================================================== WARNING: possible circular locking dependency detected 6.3.0-rc2-g68fcb3a7bf97 #4706 Not tainted ------------------------------------------------------ sco-tester/31 is trying to acquire lock: ffff8880025b8070 (&hdev->lock){+.+.}-{3:3}, at: sco_sock_getsockopt+0x1fc/0xa90 but task is already holding lock: ffff888001eeb130 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: sco_sock_getsockopt+0x104/0xa90 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}: lock_sock_nested+0x32/0x80 sco_connect_cfm+0x118/0x4a0 hci_sync_conn_complete_evt+0x1e6/0x3d0 hci_event_packet+0x55c/0x7c0 hci_rx_work+0x34c/0xa00 process_one_work+0x575/0x910 worker_thread+0x89/0x6f0 kthread+0x14e/0x180 ret_from_fork+0x2b/0x50 -> #1 (hci_cb_list_lock){+.+.}-{3:3}: __mutex_lock+0x13b/0xcc0 hci_sync_conn_complete_evt+0x1ad/0x3d0 hci_event_packet+0x55c/0x7c0 hci_rx_work+0x34c/0xa00 process_one_work+0x575/0x910 worker_thread+0x89/0x6f0 kthread+0x14e/0x180 ret_from_fork+0x2b/0x50 -> #0 (&hdev->lock){+.+.}-{3:3}: __lock_acquire+0x18cc/0x3740 lock_acquire+0x151/0x3a0 __mutex_lock+0x13b/0xcc0 sco_sock_getsockopt+0x1fc/0xa90 __sys_getsockopt+0xe9/0x190 __x64_sys_getsockopt+0x5b/0x70 do_syscall_64+0x42/0x90 entry_SYSCALL_64_after_hwframe+0x70/0xda other info that might help us debug this: Chain exists of: &hdev->lock --> hci_cb_list_lock --> sk_lock-AF_BLUETOOTH-BTPROTO_SCO Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(sk_lock-AF_BLUETOOTH-BTPROTO_SCO); lock(hci_cb_list_lock); lock(sk_lock-AF_BLUETOOTH-BTPROTO_SCO); lock(&hdev->lock); *** DEADLOCK *** 1 lock held by sco-tester/31: #0: ffff888001eeb130 (sk_lock-AF_BLUETOOTH-BTPROTO_SCO){+.+.}-{0:0}, at: sco_sock_getsockopt+0x104/0xa90 Fixes: 248733e87d50 ("Bluetooth: Allow querying of supported offload codecs over SCO socket") Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Sasha Levin --- net/bluetooth/sco.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c index 1111da4e2f2bd..1755f91a66f6a 100644 --- a/net/bluetooth/sco.c +++ b/net/bluetooth/sco.c @@ -1129,6 +1129,8 @@ static int sco_sock_getsockopt(struct socket *sock, int level, int optname, break; } + release_sock(sk); + /* find total buffer size required to copy codec + caps */ hci_dev_lock(hdev); list_for_each_entry(c, &hdev->local_codecs, list) { @@ -1146,15 +1148,13 @@ static int sco_sock_getsockopt(struct socket *sock, int level, int optname, buf_len += sizeof(struct bt_codecs); if (buf_len > len) { hci_dev_put(hdev); - err = -ENOBUFS; - break; + return -ENOBUFS; } ptr = optval; if (put_user(num_codecs, ptr)) { hci_dev_put(hdev); - err = -EFAULT; - break; + return -EFAULT; } ptr += sizeof(num_codecs); @@ -1194,12 +1194,14 @@ static int sco_sock_getsockopt(struct socket *sock, int level, int optname, ptr += len; } - if (!err && put_user(buf_len, optlen)) - err = -EFAULT; - hci_dev_unlock(hdev); hci_dev_put(hdev); + lock_sock(sk); + + if (!err && put_user(buf_len, optlen)) + err = -EFAULT; + break; default: -- 2.39.2