# \[PATCH\] backlight: pcf50633: pdata may be a null pointer, null pointer dereference cause crash

- From: Wenjia Zhao \<hidden\>
- Date: 2021-02-01 14:46:12 
- List: linux-fbdev
- Page: https://ratatoskr.run/linux-fbdev/2021/02/6253806
- Thread: https://ratatoskr.run/dri-devel/2021/02/6253806/t.md

```text
Signed-off-by: Wenjia Zhao <redacted>
---
 drivers/video/backlight/pcf50633-backlight.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/video/backlight/pcf50633-backlight.c b/drivers/video/backlight/pcf50633-backlight.c
index 540dd338..43267af 100644
--- a/drivers/video/backlight/pcf50633-backlight.c
+++ b/drivers/video/backlight/pcf50633-backlight.c
@@ -127,7 +127,8 @@ static int pcf50633_bl_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, pcf_bl);
 
-	pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDDIM, pdata->ramp_time);
+  if (pdata)
+    pcf50633_reg_write(pcf_bl->pcf, PCF50633_REG_LEDDIM, pdata->ramp_time);
 
 	/*
 	 * Should be different from bl_props.brightness, so we do not exit
-- 
2.7.4

```