rtc: pl031: fix rtc features null pointer dereference

When there is no interrupt line, rtc alarm feature is disabled.

The clearing of the alarm feature bit was being done prior to allocations
of ldata->rtc device, resulting in a null pointer dereference.

Clear RTC_FEATURE_ALARM after the rtc device is allocated.

Fixes: d9b0dd54a194 ("rtc: pl031: use RTC_FEATURE_ALARM")
Cc: stable@vger.kernel.org
Signed-off-by: Ali Pouladi <quic_apouladi@quicinc.com>
Signed-off-by: Elliot Berman <quic_eberman@quicinc.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20220225161924.274141-1-quic_eberman@quicinc.com

diff --git a/drivers/rtc/rtc-pl031.c b/drivers/rtc/rtc-pl031.c
index e38ee8848385505743d900cb1eed6bbfc5ff54c5..bad6a5d9c6839ca70905e3d46286b9729c1fd435 100644 (file)
--- a/drivers/rtc/rtc-pl031.c
+++ b/drivers/rtc/rtc-pl031.c
@@ -350,9 +350,6 @@ static int pl031_probe(struct amba_device *adev, const struct amba_id *id)
                }
        }
 
-       if (!adev->irq[0])
-               clear_bit(RTC_FEATURE_ALARM, ldata->rtc->features);
-
        device_init_wakeup(&adev->dev, true);
        ldata->rtc = devm_rtc_allocate_device(&adev->dev);
        if (IS_ERR(ldata->rtc)) {
@@ -360,6 +357,9 @@ static int pl031_probe(struct amba_device *adev, const struct amba_id *id)
                goto out;
        }
 
+       if (!adev->irq[0])
+               clear_bit(RTC_FEATURE_ALARM, ldata->rtc->features);
+
        ldata->rtc->ops = ops;
        ldata->rtc->range_min = vendor->range_min;
        ldata->rtc->range_max = vendor->range_max;