[PATCH 5.16 0109/1017] rtc: pl031: fix rtc features null pointer dereference

Greg Kroah-Hartman
2022-04-05T11:16:38Z

From: Ali Pouladi <quic_apouladi@quicinc.com>

commit ea6af39f3da50c86367a71eb3cc674ade3ed244c upstream.

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
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/rtc/rtc-pl031.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

--- a/drivers/rtc/rtc-pl031.c
+++ b/drivers/rtc/rtc-pl031.c
@@ -350,9 +350,6 @@ static int pl031_probe(struct amba_devic
}
}

- 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_devic
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;