rtc: gemini: add return value validation

Function devm_ioremap() will return a NULL pointer if it fails to remap
IO address, and its return value should be validated before it is used.
However, in function gemini_rtc_probe(), its return value is not
checked. This may result in bad memory access bugs on future access,
e.g. calling the function gemini_rtc_read_time().

Signed-off-by: Pan Bian <bianpan2016@163.com>
Acked-by: Hans Ulli Kroll <ulli.kroll@googlemail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>

diff --git a/drivers/rtc/rtc-gemini.c b/drivers/rtc/rtc-gemini.c
index ccf0dbadb62d16d7c512fffb9fc37efb7fcac7b8..5279390bb42da84d5f477a3098d7af39c3599e8c 100644 (file)
--- a/drivers/rtc/rtc-gemini.c
+++ b/drivers/rtc/rtc-gemini.c
@@ -139,6 +139,8 @@ static int gemini_rtc_probe(struct platform_device *pdev)
 
        rtc->rtc_base = devm_ioremap(dev, res->start,
                                     resource_size(res));
+       if (!rtc->rtc_base)
+               return -ENOMEM;
 
        ret = devm_request_irq(dev, rtc->rtc_irq, gemini_rtc_interrupt,
                               IRQF_SHARED, pdev->name, dev);