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 X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED 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 23D5DC43441 for ; Sun, 11 Nov 2018 20:15:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E27A02080D for ; Sun, 11 Nov 2018 20:15:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E27A02080D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=decadent.org.uk Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731798AbeKLGFL (ORCPT ); Mon, 12 Nov 2018 01:05:11 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:53042 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731042AbeKLGFK (ORCPT ); Mon, 12 Nov 2018 01:05:10 -0500 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1gLvt4-0000lK-VJ; Sun, 11 Nov 2018 19:59:15 +0000 Received: from ben by deadeye with local (Exim 4.91) (envelope-from ) id 1gLvsR-0001Vp-55; Sun, 11 Nov 2018 19:58:35 +0000 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Rob Herring" , "Srinivas Kandagatla" Date: Sun, 11 Nov 2018 19:49:05 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 112/366] of: platform: stop accessing invalid dev in of_platform_device_destroy In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.61-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Srinivas Kandagatla commit 522811e944ed9b36806faa019faec10f9d259cca upstream. Immediately after the platform_device_unregister() the device will be cleaned up. Accessing the freed pointer immediately after that will crash the system. Found this bug when kernel is built with CONFIG_PAGE_POISONING and testing loading/unloading audio drivers in a loop on Qcom platforms. Fix this by moving of_node_clear_flag() just before the unregister calls. Below is the crash trace: Unable to handle kernel paging request at virtual address 6b6b6b6b6b6c03 Mem abort info: ESR = 0x96000021 Exception class = DABT (current EL), IL = 32 bits SET = 0, FnV = 0 EA = 0, S1PTW = 0 Data abort info: ISV = 0, ISS = 0x00000021 CM = 0, WnR = 0 [006b6b6b6b6b6c03] address between user and kernel address ranges Internal error: Oops: 96000021 [#1] PREEMPT SMP Modules linked in: CPU: 2 PID: 1784 Comm: sh Tainted: G W 4.17.0-rc7-02230-ge3a63a7ef641-dirty #204 Hardware name: Qualcomm Technologies, Inc. APQ 8016 SBC (DT) pstate: 80000005 (Nzcv daif -PAN -UAO) pc : clear_bit+0x18/0x2c lr : of_platform_device_destroy+0x64/0xb8 sp : ffff00000c9c3930 x29: ffff00000c9c3930 x28: ffff80003d39b200 x27: ffff000008bb1000 x26: 0000000000000040 x25: 0000000000000124 x24: ffff80003a9a3080 x23: 0000000000000060 x22: ffff00000939f518 x21: ffff80003aa79e98 x20: ffff80003aa3dae0 x19: ffff80003aa3c890 x18: ffff800009feb794 x17: 0000000000000000 x16: 0000000000000000 x15: ffff800009feb790 x14: 0000000000000000 x13: ffff80003a058778 x12: ffff80003a058728 x11: ffff80003a058750 x10: 0000000000000000 x9 : 0000000000000006 x8 : ffff80003a825988 x7 : bbbbbbbbbbbbbbbb x6 : 0000000000000001 x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000000008 x2 : 0000000000000001 x1 : 6b6b6b6b6b6b6c03 x0 : 0000000000000000 Process sh (pid: 1784, stack limit = 0x (ptrval)) Call trace: clear_bit+0x18/0x2c q6afe_remove+0x20/0x38 apr_device_remove+0x30/0x70 device_release_driver_internal+0x170/0x208 device_release_driver+0x14/0x20 bus_remove_device+0xcc/0x150 device_del+0x10c/0x310 device_unregister+0x1c/0x70 apr_remove_device+0xc/0x18 device_for_each_child+0x50/0x80 apr_remove+0x18/0x20 rpmsg_dev_remove+0x38/0x68 device_release_driver_internal+0x170/0x208 device_release_driver+0x14/0x20 bus_remove_device+0xcc/0x150 device_del+0x10c/0x310 device_unregister+0x1c/0x70 qcom_smd_remove_device+0xc/0x18 device_for_each_child+0x50/0x80 qcom_smd_unregister_edge+0x3c/0x70 smd_subdev_remove+0x18/0x28 rproc_stop+0x48/0xd8 rproc_shutdown+0x60/0xe8 state_store+0xbc/0xf8 dev_attr_store+0x18/0x28 sysfs_kf_write+0x3c/0x50 kernfs_fop_write+0x118/0x1e0 __vfs_write+0x18/0x110 vfs_write+0xa4/0x1a8 ksys_write+0x48/0xb0 sys_write+0xc/0x18 el0_svc_naked+0x30/0x34 Code: d2800022 8b400c21 f9800031 9ac32043 (c85f7c22) ---[ end trace 32020935775616a2 ]--- Signed-off-by: Srinivas Kandagatla Signed-off-by: Rob Herring [bwh: Backported to 3.16: There's no OF_POPULATED_BUS flag] Signed-off-by: Ben Hutchings --- drivers/of/platform.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) --- a/drivers/of/platform.c +++ b/drivers/of/platform.c @@ -522,6 +522,8 @@ static int of_platform_device_destroy(st return 0; } + of_node_clear_flag(dev->of_node, OF_POPULATED); + if (dev->bus == &platform_bus_type) platform_device_unregister(to_platform_device(dev)); #ifdef CONFIG_ARM_AMBA @@ -533,8 +535,6 @@ static int of_platform_device_destroy(st return 0; } - of_node_clear_flag(dev->of_node, OF_POPULATED); - return 0; }