From patchwork Wed May 25 10:56:51 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [V2,3/5] rtc: stmp3xxx: Initialize drvdata before registering device Date: Wed, 25 May 2011 00:56:51 -0000 From: Wolfram Sang X-Patchwork-Id: 97326 Message-Id: <1306321013-28364-4-git-send-email-w.sang@pengutronix.de> To: rtc-linux@googlegroups.com Cc: linux-arm-kernel@lists.infradead.org, John Stultz , Andrew Morton , Wolfram Sang Commit f44f7f96a20 ("RTC: Initialize kernel state from RTC") uncovered an issue in a number of RTC drivers, where the drivers call rtc_device_register before initializing the device or platform drvdata. This frequently results in null pointer dereferences when the rtc_device_register immediately makes use of the rtc device, calling rtc_read_alarm. The solution is to ensure the drvdata is initialized prior to registering the rtc device. Signed-off-by: Wolfram Sang Tested-by: Shawn Guo --- Thanks to John for the commit-msg ;) drivers/rtc/rtc-stmp3xxx.c | 7 +++++-- 1 files changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/rtc/rtc-stmp3xxx.c b/drivers/rtc/rtc-stmp3xxx.c index 44e2202..fae563a 100644 --- a/drivers/rtc/rtc-stmp3xxx.c +++ b/drivers/rtc/rtc-stmp3xxx.c @@ -172,6 +172,7 @@ static int stmp3xxx_rtc_remove(struct platform_device *pdev) free_irq(rtc_data->irq_alarm, &pdev->dev); free_irq(rtc_data->irq_1msec, &pdev->dev); rtc_device_unregister(rtc_data->rtc); + platform_set_drvdata(pdev, NULL); iounmap(rtc_data->io); kfree(rtc_data); @@ -212,11 +213,14 @@ static int stmp3xxx_rtc_probe(struct platform_device *pdev) goto out_remap; } + platform_set_drvdata(pdev, rtc_data); + mxs_reset_block(rtc_data->io); __mxs_clrl(STMP3XXX_RTC_PERSISTENT0_ALARM_EN | STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE_EN | STMP3XXX_RTC_PERSISTENT0_ALARM_WAKE, rtc_data->io + STMP3XXX_RTC_PERSISTENT0); + rtc_data->rtc = rtc_device_register(pdev->name, &pdev->dev, &stmp3xxx_rtc_ops, THIS_MODULE); if (IS_ERR(rtc_data->rtc)) { @@ -240,8 +244,6 @@ static int stmp3xxx_rtc_probe(struct platform_device *pdev) goto out_irq1; } - platform_set_drvdata(pdev, rtc_data); - return 0; out_irq1: @@ -251,6 +253,7 @@ out_irq_alarm: rtc_data->io + STMP3XXX_RTC_CTRL); rtc_device_unregister(rtc_data->rtc); out_remap: + platform_set_drvdata(pdev, NULL); iounmap(rtc_data->io); out_free: kfree(rtc_data);