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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B419AEEB562 for ; Fri, 8 Sep 2023 18:22:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1344390AbjIHSWR (ORCPT ); Fri, 8 Sep 2023 14:22:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58596 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343902AbjIHSVD (ORCPT ); Fri, 8 Sep 2023 14:21:03 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BF9F12718; Fri, 8 Sep 2023 11:19:16 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C5AA8C433D9; Fri, 8 Sep 2023 18:18:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1694197127; bh=IdQA7SAebVFhVC8OCYuj+C4VeCRGZDopFCvDA7B6W74=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=V17oBKklP1uzKHYxopOq322kSYjfXJNVpcEEwnf9mqlFxelL2h/myAkIoXoCO1+J7 yHtUjOHuKRba95DE8xq9uiSNqxF8nLPtyC6ZtFCon7WlOI5khE9sQ8QenSZJASunjl rJx4gGJAJedu/BR1p/k5uhVH2yWReyHm1ZuX6rMTfvzb0txJwsJQBiMncr7L9k6fwR ZExLi7M1Ca6eeTU8hlKz5vrMjrw5xUmQxOdvbQRmGz6h0WwVd7xrOiT4gx3aL5Y8FY fEO1vSaPa6xIe7XJzc0GTKOBfdaTZ4LFndCk/Qm4u+tU3oUxrNipb/b/R10o5LIgPD BuiLnt8cOFtNg== From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Ying Hsu , Luiz Augusto von Dentz , Sasha Levin , marcel@holtmann.org, johan.hedberg@gmail.com, luiz.dentz@gmail.com, linux-bluetooth@vger.kernel.org Subject: [PATCH AUTOSEL 6.1 14/26] Bluetooth: Fix hci_suspend_sync crash Date: Fri, 8 Sep 2023 14:17:52 -0400 Message-Id: <20230908181806.3460164-14-sashal@kernel.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230908181806.3460164-1-sashal@kernel.org> References: <20230908181806.3460164-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.1.52 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ying Hsu [ Upstream commit 573ebae162111063eedc6c838a659ba628f66a0f ] If hci_unregister_dev() frees the hci_dev object but hci_suspend_notifier may still be accessing it, it can cause the program to crash. Here's the call trace: <4>[102152.653246] Call Trace: <4>[102152.653254] hci_suspend_sync+0x109/0x301 [bluetooth] <4>[102152.653259] hci_suspend_dev+0x78/0xcd [bluetooth] <4>[102152.653263] hci_suspend_notifier+0x42/0x7a [bluetooth] <4>[102152.653268] notifier_call_chain+0x43/0x6b <4>[102152.653271] __blocking_notifier_call_chain+0x48/0x69 <4>[102152.653273] __pm_notifier_call_chain+0x22/0x39 <4>[102152.653276] pm_suspend+0x287/0x57c <4>[102152.653278] state_store+0xae/0xe5 <4>[102152.653281] kernfs_fop_write+0x109/0x173 <4>[102152.653284] __vfs_write+0x16f/0x1a2 <4>[102152.653287] ? selinux_file_permission+0xca/0x16f <4>[102152.653289] ? security_file_permission+0x36/0x109 <4>[102152.653291] vfs_write+0x114/0x21d <4>[102152.653293] __x64_sys_write+0x7b/0xdb <4>[102152.653296] do_syscall_64+0x59/0x194 <4>[102152.653299] entry_SYSCALL_64_after_hwframe+0x5c/0xc1 This patch holds the reference count of the hci_dev object while processing it in hci_suspend_notifier to avoid potential crash caused by the race condition. Signed-off-by: Ying Hsu Signed-off-by: Luiz Augusto von Dentz Signed-off-by: Sasha Levin --- net/bluetooth/hci_core.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c index d034bf2a999e1..146ad00ad1b9c 100644 --- a/net/bluetooth/hci_core.c +++ b/net/bluetooth/hci_core.c @@ -2436,6 +2436,9 @@ static int hci_suspend_notifier(struct notifier_block *nb, unsigned long action, if (hci_dev_test_flag(hdev, HCI_USER_CHANNEL)) return NOTIFY_DONE; + /* To avoid a potential race with hci_unregister_dev. */ + hci_dev_hold(hdev); + if (action == PM_SUSPEND_PREPARE) ret = hci_suspend_dev(hdev); else if (action == PM_POST_SUSPEND) @@ -2445,6 +2448,7 @@ static int hci_suspend_notifier(struct notifier_block *nb, unsigned long action, bt_dev_err(hdev, "Suspend notifier action (%lu) failed: %d", action, ret); + hci_dev_put(hdev); return NOTIFY_DONE; } -- 2.40.1