From patchwork Tue Jul 4 20:36:27 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sergey Shtylyov X-Patchwork-Id: 699212 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 30D0CEB64D9 for ; Tue, 4 Jul 2023 20:36:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230326AbjGDUgm (ORCPT ); Tue, 4 Jul 2023 16:36:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49756 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229647AbjGDUgl (ORCPT ); Tue, 4 Jul 2023 16:36:41 -0400 Received: from mx01.omp.ru (mx01.omp.ru [90.154.21.10]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ECFBEE7B for ; Tue, 4 Jul 2023 13:36:38 -0700 (PDT) Received: from [192.168.1.103] (31.173.85.51) by msexch01.omp.ru (10.188.4.12) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.2.986.14; Tue, 4 Jul 2023 23:36:28 +0300 From: Sergey Shtylyov Subject: [PATCH v3] usb: host: xhci-plat: fix possible kernel oops while resuming To: Mathias Nyman , Greg Kroah-Hartman , CC: Florian Fainelli Organization: Open Mobile Platform Message-ID: Date: Tue, 4 Jul 2023 23:36:27 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 Content-Language: en-US X-Originating-IP: [31.173.85.51] X-ClientProxiedBy: msexch01.omp.ru (10.188.4.12) To msexch01.omp.ru (10.188.4.12) X-KSE-ServerInfo: msexch01.omp.ru, 9 X-KSE-AntiSpam-Interceptor-Info: scan successful X-KSE-AntiSpam-Version: 5.9.59, Database issued on: 07/04/2023 20:17:24 X-KSE-AntiSpam-Status: KAS_STATUS_NOT_DETECTED X-KSE-AntiSpam-Method: none X-KSE-AntiSpam-Rate: 59 X-KSE-AntiSpam-Info: Lua profiles 178432 [Jul 04 2023] X-KSE-AntiSpam-Info: Version: 5.9.59.0 X-KSE-AntiSpam-Info: Envelope from: s.shtylyov@omp.ru X-KSE-AntiSpam-Info: LuaCore: 520 520 ccb018a655251011855942a2571029252d3d69a2 X-KSE-AntiSpam-Info: {rep_avail} X-KSE-AntiSpam-Info: {Tracking_from_domain_doesnt_match_to} X-KSE-AntiSpam-Info: {relay has no DNS name} X-KSE-AntiSpam-Info: {SMTP from is not routable} X-KSE-AntiSpam-Info: {Found in DNSBL: 31.173.85.51 in (user) b.barracudacentral.org} X-KSE-AntiSpam-Info: 127.0.0.199:7.1.2; omp.ru:7.1.1; 31.173.85.51:7.7.3; d41d8cd98f00b204e9800998ecf8427e.com:7.1.1 X-KSE-AntiSpam-Info: ApMailHostAddress: 31.173.85.51 X-KSE-AntiSpam-Info: {DNS response errors} X-KSE-AntiSpam-Info: Rate: 59 X-KSE-AntiSpam-Info: Status: not_detected X-KSE-AntiSpam-Info: Method: none X-KSE-AntiSpam-Info: Auth:dmarc=temperror header.from=omp.ru;spf=temperror smtp.mailfrom=omp.ru;dkim=none X-KSE-Antiphishing-Info: Clean X-KSE-Antiphishing-ScanningType: Heuristic X-KSE-Antiphishing-Method: None X-KSE-Antiphishing-Bases: 07/04/2023 20:22:00 X-KSE-Antivirus-Interceptor-Info: scan successful X-KSE-Antivirus-Info: Clean, bases: 7/4/2023 5:02:00 PM X-KSE-Attachment-Filter-Triggered-Rules: Clean X-KSE-Attachment-Filter-Triggered-Filters: Clean X-KSE-BulkMessagesFiltering-Scan-Result: InTheLimit Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org If this driver enables the xHC clocks while resuming from sleep, it calls clk_prepare_enable() without checking for errors and blithely goes on to read/write the xHC's registers -- which, with the xHC not being clocked, at least on ARM32 usually causes an imprecise external abort exceptions which cause kernel oops. Currently, the chips for which the driver does the clock dance on suspend/resume seem to be the Broadcom STB SoCs, based on ARM32 CPUs, as it seems... In order to fix this issue, add the result checks for clk_prepare_enable() calls in xhci_plat_resume(), add conditional clk_disable_unprepare() calls on the error path of xhci_plat_resume(); then factor out the common clock disabling code from the suspend() and resume() driver PM methods into a separate function to avoid code duplication. Found by Linux Verification Center (linuxtesting.org) with the Svace static analysis tool. Fixes: 8bd954c56197 ("usb: host: xhci-plat: suspend and resume clocks") Signed-off-by: Sergey Shtylyov --- This patch is against the 'usb-linus' branch of Greg KH's 'usb.git' repo... Changes in version 3: - sanitized the clock enabling error paths in xhci_plat_resume() WRT the applicability checks; - factored out the common clock disabling code from the suspend() and resume() driver PM methods; - added to the patch sescriptiun a passage describing the change being done. Changes in version 2: - fixed up the error path for clk_prepare_enable() calls in xhci_plat_resume(). drivers/usb/host/xhci-plat.c | 35 +++++++++++++++++++++++++++-------- 1 file changed, 27 insertions(+), 8 deletions(-) Index: usb/drivers/usb/host/xhci-plat.c =================================================================== --- usb.orig/drivers/usb/host/xhci-plat.c +++ usb/drivers/usb/host/xhci-plat.c @@ -435,6 +435,14 @@ int xhci_plat_remove(struct platform_dev } EXPORT_SYMBOL_GPL(xhci_plat_remove); +static void xhci_plat_disable_clocks(struct xhci_hcd *xhci) +{ + if (xhci->quirks & XHCI_SUSPEND_RESUME_CLKS) { + clk_disable_unprepare(xhci->clk); + clk_disable_unprepare(xhci->reg_clk); + } +} + static int __maybe_unused xhci_plat_suspend(struct device *dev) { struct usb_hcd *hcd = dev_get_drvdata(dev); @@ -455,10 +463,8 @@ static int __maybe_unused xhci_plat_susp if (ret) return ret; - if (!device_may_wakeup(dev) && (xhci->quirks & XHCI_SUSPEND_RESUME_CLKS)) { - clk_disable_unprepare(xhci->clk); - clk_disable_unprepare(xhci->reg_clk); - } + if (!device_may_wakeup(dev)) + xhci_plat_disable_clocks(xhci); return 0; } @@ -470,23 +476,36 @@ static int __maybe_unused xhci_plat_resu int ret; if (!device_may_wakeup(dev) && (xhci->quirks & XHCI_SUSPEND_RESUME_CLKS)) { - clk_prepare_enable(xhci->clk); - clk_prepare_enable(xhci->reg_clk); + ret = clk_prepare_enable(xhci->clk); + if (ret) + return ret; + + ret = clk_prepare_enable(xhci->reg_clk); + if (ret) { + clk_disable_unprepare(xhci->clk); + return ret; + } } ret = xhci_priv_resume_quirk(hcd); if (ret) - return ret; + goto disable_clks; ret = xhci_resume(xhci, 0); if (ret) - return ret; + goto disable_clks; pm_runtime_disable(dev); pm_runtime_set_active(dev); pm_runtime_enable(dev); return 0; + +disable_clks: + if (!device_may_wakeup(dev)) + xhci_plat_disable_clocks(xhci); + + return ret; } static int __maybe_unused xhci_plat_runtime_suspend(struct device *dev)