rtc: 88pm80x: fix possible race condition

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.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>

1 files changed, 8 insertions, 4 deletions

diff --git a/drivers/rtc/rtc-88pm80x.c b/drivers/rtc/rtc-88pm80x.c
index f60c0d73c2f3..dae527f8c58e 100644
--- a/drivers/rtc/rtc-88pm80x.c
+++ b/drivers/rtc/rtc-88pm80x.c
@@ -290,6 +290,10 @@ static int pm80x_rtc_probe(struct platform_device *pdev)
         info->dev = &pdev->dev;
         dev_set_drvdata(&pdev->dev, info);
 
+        info->rtc_dev = devm_rtc_allocate_device(&pdev->dev);
+        if (IS_ERR(info->rtc_dev))
+                return PTR_ERR(info->rtc_dev);
+
         ret = pm80x_request_irq(chip, info->irq, rtc_update_handler,
                                 IRQF_ONESHOT, "rtc", info);
         if (ret < 0) {
@@ -298,10 +302,10 @@ static int pm80x_rtc_probe(struct platform_device *pdev)
                 goto out;
         }
 
-        info->rtc_dev = devm_rtc_device_register(&pdev->dev, "88pm80x-rtc",
-                                            &pm80x_rtc_ops, THIS_MODULE);
-        if (IS_ERR(info->rtc_dev)) {
-                ret = PTR_ERR(info->rtc_dev);
+        info->rtc_dev->ops = &pm80x_rtc_ops;
+
+        ret = rtc_register_device(info->rtc_dev);
+        if (ret) {
                 dev_err(&pdev->dev, "Failed to register RTC device: %d\n", ret);
                 goto out_rtc;
         }