Re: [PATCH] net: stmmac: fix a potential NULL pointer dereference

From: Mukesh Ojha <redacted>
Date: Tue, 26 Mar 2019 15:27:03 +0530

On 3/23/2019 9:09 AM, Kangjie Lu wrote:

quoted

In case of_device_get_match_data fails, the fix return -EINVAL
to avoid the NULL pointer dereference.

Signed-off-by: Kangjie Lu <redacted>
---
  drivers/net/ethernet/stmicro/stmmac/dwmac-dwc-qos-eth.c | 2 ++
  1 file changed, 2 insertions(+)

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-dwc-qos-eth.c

b/drivers/net/ethernet/stmicro/stmmac/dwmac-dwc-qos-eth.c
index 3256e5cbad27..344ead5949b1 100644

--- a/drivers/net/ethernet/stmicro/stmmac/dwmac-dwc-qos-eth.c
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-dwc-qos-eth.c

@@ -485,6 +485,8 @@ static int dwc_eth_dwmac_remove(struct

platform_device *pdev)
  	int err;
    	data = of_device_get_match_data(&pdev->dev);
+	if (!data)
+		return -EINVAL;

Although, it is false alarm for this driver as of_match_table is not
NULL, but it would be good to add the check.

I disagree.

This is adding a check just for the sake of adding the check and
shutting up a static analysis tool.

Now, if the tool looked at the table entries being fed into this
function, and found such a posibility then we would fix the bug
and still not add the check.