On 22/05/18 12:46, Wei Yongjun wrote:

platform_get_resource() may fail and return NULL, so we should better check it's return value to avoid a NULL pointer dereference a bit later in the code.

This is detected by Coccinelle semantic patch.

@@ expression pdev, res, n, t, e, e1, e2; @@

res = platform_get_resource_byname(pdev, t, n);

• if (!res)
• return -EINVAL;

... when != res == NULL e = devm_ioremap(e1, res->start, e2);

Fixes: ad7fcbc308b0 ("slimbus: qcom: Add Qualcomm Slimbus controller driver") Signed-off-by: Wei Yongjun weiyongjun1@huawei.com

---

drivers/slimbus/qcom-ctrl.c | 2 ++ 1 file changed, 2 insertions(+)

diff --git a/drivers/slimbus/qcom-ctrl.c b/drivers/slimbus/qcom-ctrl.c index bb36a8f..caea3b9 100644 --- a/drivers/slimbus/qcom-ctrl.c +++ b/drivers/slimbus/qcom-ctrl.c @@ -478,6 +478,8 @@ static void qcom_slim_prg_slew(struct platform_device *pdev, /* SLEW RATE register for this SLIMbus */ slew_mem = platform_get_resource_byname(pdev, IORESOURCE_MEM, "slew");

• if (!slew_mem)
  

• 	return;
  

I think a better fix would be to do a devm_ioremap_resource() instead of devm_ioremap, which already has this check. This will also be inline with other resource handled in this driver.

thanks, srini

ctrl->slew_reg = devm_ioremap(&pdev->dev, slew_mem->start,
		resource_size(slew_mem));
if (!ctrl->slew_reg)