Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933405AbbLHQkz (ORCPT ); Tue, 8 Dec 2015 11:40:55 -0500 Received: from mail1.bemta3.messagelabs.com ([195.245.230.176]:15582 "EHLO mail1.bemta3.messagelabs.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752698AbbLHQkx (ORCPT ); Tue, 8 Dec 2015 11:40:53 -0500 X-Greylist: delayed 403 seconds by postgrey-1.27 at vger.kernel.org; Tue, 08 Dec 2015 11:40:53 EST X-Env-Sender: stwiss.opensource@diasemi.com X-Msg-Ref: server-7.tower-39.messagelabs.com!1449592447!10864646!1 X-Originating-IP: [94.185.165.51] X-StarScan-Received: X-StarScan-Version: 7.19.2; banners=-,-,- X-VirusChecked: Checked From: Steve Twiss Date: Tue, 8 Dec 2015 16:28:39 +0000 Subject: [PATCH V1] rtc: da9063: access ordering error during RTC interrupt system power on To: Alessandro Zummo , Alexandre Belloni , LINUXKERNEL , RTC-LINUX CC: David Dajun Chen , Support Opensource Message-ID: <20151208163406.B34683FB25@swsrvapps-01.diasemi.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2782 Lines: 88 From: Steve Twiss This fix alters the ordering of the IRQ and device registrations in the RTC driver probe function. This change will apply to the RTC driver that supports both DA9063 and DA9062 PMICs. A problem could occur with the existing RTC driver if: A system is started from a cold boot using the PMIC RTC IRQ to initiate a power on operation. For instance, if an RTC alarm is used to start a platform from power off. The existing driver IRQ is requested before the device has been properly registered. i.e. ret = devm_request_threaded_irq() comes before rtc->rtc_dev = devm_rtc_device_register(); In this case, the interrupt can be called before the device has been registered and the handler can be called immediately. The IRQ handler da9063_alarm_event() contains the function call rtc_update_irq(rtc->rtc_dev, 1, RTC_IRQF | RTC_AF); which in turn tries to access the unavailable rtc->rtc_dev. The fix is to reorder the functions inside the RTC probe. The IRQ is requested after the RTC device resource has been registered so that get_irq_byname is the last thing to happen. Signed-off-by: Steve Twiss --- This patch applies against linux-next and v4.4-rc4 Regards, Steve drivers/rtc/rtc-da9063.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-) diff --git a/drivers/rtc/rtc-da9063.c b/drivers/rtc/rtc-da9063.c index 284b587..d6c853b 100644 --- a/drivers/rtc/rtc-da9063.c +++ b/drivers/rtc/rtc-da9063.c @@ -483,24 +483,23 @@ static int da9063_rtc_probe(struct platform_device *pdev) platform_set_drvdata(pdev, rtc); + rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, DA9063_DRVNAME_RTC, + &da9063_rtc_ops, THIS_MODULE); + if (IS_ERR(rtc->rtc_dev)) + return PTR_ERR(rtc->rtc_dev); + + da9063_data_to_tm(data, &rtc->alarm_time, rtc); + rtc->rtc_sync = false; + irq_alarm = platform_get_irq_byname(pdev, "ALARM"); ret = devm_request_threaded_irq(&pdev->dev, irq_alarm, NULL, da9063_alarm_event, IRQF_TRIGGER_LOW | IRQF_ONESHOT, "ALARM", rtc); - if (ret) { + if (ret) dev_err(&pdev->dev, "Failed to request ALARM IRQ %d: %d\n", irq_alarm, ret); - return ret; - } - - rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, DA9063_DRVNAME_RTC, - &da9063_rtc_ops, THIS_MODULE); - if (IS_ERR(rtc->rtc_dev)) - return PTR_ERR(rtc->rtc_dev); - da9063_data_to_tm(data, &rtc->alarm_time, rtc); - rtc->rtc_sync = false; return ret; } -- end-of-patch for PATCH V1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/