From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 CEBA73E1CED; Fri, 28 Aug 2026 08:55:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787907311; cv=none; b=sTQGzu5osfeUrwsslD4NYq39pYPfyFzSdtMTbxNXQvFTJsmCg9Vqpdhvz74ZtaSRW4t1qYUtq+/b7yTDQS6RsUh3fgq/TBLgenOtQn2m9LC2JAYG/TVJ4LbWg1ovd/cWqx19uhtfL9qQSRWZufoo2a2SbQTyB2LhEg5ZgNzxMO8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787907311; c=relaxed/simple; bh=sNyIB/GT50g8rb6JAtiKZ2puJnLCBSlc8IgLMZWXwZg=; h=From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type:Date; b=FyG3Fdv/O3am529NSuz+pQnnfdYDz7rwJZqYIl4mOGqNqPn85F4cosEyWpIETpw9yhU98XyFV1F8wvmaBzjeskbgZKbw5m4LMmGBFpOiOMyHj7N3mQYp+nllN8TV/CjZxe18DYt1XnTDl64vM46p+9PhLfsjL0qTfb5VvMVpgRo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=mLL3C5H9; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="mLL3C5H9" Received: by smtp.kernel.org (Postfix) with UTF8SMTPSA id 180311F000E9; Fri, 28 Aug 2026 08:55:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787907309; bh=5BzL+9Md99aFW4pTj/6ay3UfAZXHl/2F0v7SSFjgOrA=; h=From:To:Cc:Subject:Date; b=mLL3C5H9RQ29Opb+VmilHMI1/BnLKoDKarw4wDdW5ECbykY48mVBux5S8ZYxNK22j QcA91g3qOO3eBLaGSYd5uBs0vPA/wHTq4VTqH2EjTIpoYR59XaPTfBMbHhYuxWxfjb 9srq+Po3qKvTy7nPgFtTr15gpvcMujM7TPjwUi1vfCsgyyAjnjEC5H0oDjiqraBkMR t9cj9rvK19vNz100hnZQtwEoSLqoqz3d3lXZGjwxgu5mgk41x1mwaZAhW7J/vC7UVR un7AjwYDSgjvb2kuwUnq4L7Ve3Z1PLtWoOfqD5cmVIMOGzVSZAOND7bkYzMu/sH3Su 2FE6HbgFDiRDg== From: "syzbot" To: syzkaller-bugs@googlegroups.com, Aleksandr Nogikh , , "Luiz Augusto von Dentz" , "Marcel Holtmann" , "Hilda Wu" Cc: linux-kernel@vger.kernel.org, syzbot@lists.linux.dev Subject: [PATCH] Bluetooth: hci_core: Fix race condition during device registration Message-ID: <7f282e86-b9fa-4a3d-8dea-208975771b35@mail.kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Date: Fri, 28 Aug 2026 08:55:09 +0000 (UTC) From: Aleksandr Nogikh In hci_register_dev(), the power_on work item is queued to hdev->req_workqueue before initializing hdev->adv_monitors_idr and registering the MSFT extension via msft_register(). For devices marked with quirks such as HCI_QUIRK_RAW_DEVICE, the HCI_UNCONFIGURED flag is set on the device. When the power_on work item runs concurrently on another CPU, hci_power_on() detects that the device is unconfigured and immediately invokes hci_dev_do_close(), which calls msft_do_close(). Concurrently, msft_register() allocates the msft structure and exposes it to hdev->msft_data prior to calling mutex_init(&msft->filter_lock). If msft_do_close() executes while hdev->msft_data is already assigned but the mutex has not yet been initialized, mutex_lock(&msft->filter_lock) operates on an uninitialized mutex, triggering a DEBUG_LOCKS warning: DEBUG_LOCKS_WARN_ON(lock->magic != lock) WARNING: kernel/locking/mutex.c:625 at __mutex_lock_common kernel/locking/mutex.c:625 [inline] WARNING: kernel/locking/mutex.c:625 at __mutex_lock+0x12d8/0x1550 kernel/locking/mutex.c:821 ... Call Trace: msft_do_close+0x308/0x7b0 net/bluetooth/msft.c:693 hci_dev_close_sync+0x86b/0x10a0 net/bluetooth/hci_sync.c:5522 hci_dev_do_close net/bluetooth/hci_core.c:499 [inline] hci_power_on+0x32c/0x750 net/bluetooth/hci_core.c:937 process_one_work kernel/workqueue.c:3322 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405 worker_thread+0x92d/0xe10 kernel/workqueue.c:3486 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Fix this by moving the queue_work() call in hci_register_dev() to after idr_init(&hdev->adv_monitors_idr) and msft_register(hdev) so that device structures and extensions are fully initialized before asynchronous tasks can access them. Additionally, assign hdev->msft_data in msft_register() only after mutex_init(&msft->filter_lock) has completed. Fixes: 9e14606d8f38 ("Bluetooth: msft: Extended monitor tracking by address filter") Assisted-by: Gemini:gemini-3.7-flash Gemini:gemini-3.1-pro-preview syzbot Reported-by: syzbot+14ce1b05b7d5a989abbe@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=14ce1b05b7d5a989abbe Link: https://syzkaller.appspot.com/ai_job?id=2bc9e8aa-ca6d-43e2-be2c-fd5d9f649d7e Signed-off-by: Aleksandr Nogikh --- diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c index 5ba9fe826..771b73c99 100644 --- a/net/bluetooth/hci_core.c +++ b/net/bluetooth/hci_core.c @@ -2629,11 +2629,11 @@ int hci_register_dev(struct hci_dev *hdev) if (error) BT_WARN("register suspend notifier failed error:%d\n", error); - queue_work(hdev->req_workqueue, &hdev->power_on); - idr_init(&hdev->adv_monitors_idr); msft_register(hdev); + queue_work(hdev->req_workqueue, &hdev->power_on); + return id; err_wqueue: diff --git a/net/bluetooth/msft.c b/net/bluetooth/msft.c index d7badce87..255163033 100644 --- a/net/bluetooth/msft.c +++ b/net/bluetooth/msft.c @@ -764,8 +764,8 @@ void msft_register(struct hci_dev *hdev) INIT_LIST_HEAD(&msft->handle_map); INIT_LIST_HEAD(&msft->address_filters); - hdev->msft_data = msft; mutex_init(&msft->filter_lock); + hdev->msft_data = msft; } void msft_release(struct hci_dev *hdev) base-commit: 8d3ae59288f1e7d58d76558a6ee96d533bc5019f -- See https://goo.gle/syzbot-ai-patches for information about AI-generated patches. The person who has signed off on the patch is responsible for addressing comments. syzbot engineers can be reached at syzkaller@googlegroups.com.