Re: [PATCH] backlight: pcf50633: pdata may be a null pointer, null pointer dereference cause crash
From: Daniel Thompson <hidden>
Date: 2021-02-02 09:26:39
Also in:
dri-devel, lkml
On Mon, Feb 01, 2021 at 08:41:38AM -0600, Wenjia Zhao wrote:
Signed-off-by: Wenjia Zhao <redacted>
There should be a patch description here explaining why the patch is needed and how it works.
quoted hunk ↗ jump to hunk
--- 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);
Assuming you found this issue using a static analyzer then I think it might be better to if an "if (!pdata) return -EINVAL" further up the file instead. In other words it is better to "document" (via the return code) that the code does not support pdata == NULL than to add another untested code path. Daniel.