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=-0.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,UNPARSEABLE_RELAY,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 B4ED5C6778D for ; Tue, 11 Sep 2018 11:32:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 41E2720866 for ; Tue, 11 Sep 2018 11:32:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 41E2720866 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=mediatek.com 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 S1726897AbeIKQbf (ORCPT ); Tue, 11 Sep 2018 12:31:35 -0400 Received: from mailgw01.mediatek.com ([210.61.82.183]:26043 "EHLO mailgw01.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726563AbeIKQbe (ORCPT ); Tue, 11 Sep 2018 12:31:34 -0400 X-UUID: 4c2ea15926ee45c89260f0c39ff4f565-20180911 Received: from mtkcas08.mediatek.inc [(172.21.101.126)] by mailgw01.mediatek.com (envelope-from ) (mhqrelay.mediatek.com ESMTP with TLS) with ESMTP id 1548744902; Tue, 11 Sep 2018 19:32:32 +0800 Received: from mtkcas09.mediatek.inc (172.21.101.178) by mtkmbs08n2.mediatek.inc (172.21.101.56) with Microsoft SMTP Server (TLS) id 15.0.1210.3; Tue, 11 Sep 2018 19:32:26 +0800 Received: from [172.21.77.4] (172.21.77.4) by mtkcas09.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1210.3 via Frontend Transport; Tue, 11 Sep 2018 19:32:26 +0800 Message-ID: <1536665546.25102.1.camel@mtksdaap41> Subject: Re: [PATCH 1/3] rtc: mt6397: fix possible race condition From: Eddie Huang To: Alexandre Belloni CC: , , , , Sean Wang Date: Tue, 11 Sep 2018 19:32:26 +0800 In-Reply-To: <20180909203848.3470-1-alexandre.belloni@bootlin.com> References: <20180909203848.3470-1-alexandre.belloni@bootlin.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.10.4-0ubuntu2 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-MTK: N Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 2018-09-09 at 22:38 +0200, Alexandre Belloni wrote: > The IRQ is requested before the struct rtc is allocated and registered, but > this struct is used in the IRQ handler. This may lead to a NULL pointer > dereference. > > Switch to devm_rtc_allocate_device/rtc_register_device to allocate the rtc > before requesting the IRQ. > > Cc: Eddie Huang > Cc: Sean Wang > Signed-off-by: Alexandre Belloni > --- > drivers/rtc/rtc-mt6397.c | 13 ++++++++----- > 1 file changed, 8 insertions(+), 5 deletions(-) > > diff --git a/drivers/rtc/rtc-mt6397.c b/drivers/rtc/rtc-mt6397.c > index 385f8303bb41..e9a25ec4d434 100644 > --- a/drivers/rtc/rtc-mt6397.c > +++ b/drivers/rtc/rtc-mt6397.c > @@ -332,6 +332,10 @@ static int mtk_rtc_probe(struct platform_device *pdev) > > platform_set_drvdata(pdev, rtc); > > + rtc->rtc_dev = devm_rtc_allocate_device(rtc->dev); > + if (IS_ERR(rtc->rtc_dev)) > + return PTR_ERR(rtc->rtc_dev); > + > ret = request_threaded_irq(rtc->irq, NULL, > mtk_rtc_irq_handler_thread, > IRQF_ONESHOT | IRQF_TRIGGER_HIGH, > @@ -344,11 +348,11 @@ static int mtk_rtc_probe(struct platform_device *pdev) > > device_init_wakeup(&pdev->dev, 1); > > - rtc->rtc_dev = rtc_device_register("mt6397-rtc", &pdev->dev, > - &mtk_rtc_ops, THIS_MODULE); > - if (IS_ERR(rtc->rtc_dev)) { > + rtc->rtc_dev->ops = &mtk_rtc_ops; > + > + ret = rtc_register_device(rtc->rtc_dev); > + if (ret) { > dev_err(&pdev->dev, "register rtc device failed\n"); > - ret = PTR_ERR(rtc->rtc_dev); > goto out_free_irq; > } > > @@ -365,7 +369,6 @@ static int mtk_rtc_remove(struct platform_device *pdev) > { > struct mt6397_rtc *rtc = platform_get_drvdata(pdev); > > - rtc_device_unregister(rtc->rtc_dev); > free_irq(rtc->irq, rtc->rtc_dev); > irq_dispose_mapping(rtc->irq); > Thanks Acked-by: Eddie Huang