Hi,
Static analysis by Coverity on today's linux-next has found an issue in
function loongson_dwmac_probe with the following commit:
commit 30bba69d7db40e732d6c0aa6d4890c60d717e314
Author: Qing Zhang [off-list ref]
Date: Fri Jun 18 10:53:34 2021 +0800
stmmac: pci: Add dwmac support for Loongson
The analysis is as follows:
110 plat->phy_interface = device_get_phy_mode(&pdev->dev);
Enum compared against 0
(NO_EFFECT)
unsigned_compare: This less-than-zero comparison of an
unsigned value is never true. plat->phy_interface < 0U.
111 if (plat->phy_interface < 0)
112 dev_err(&pdev->dev, "phy_mode not found\n");
Enum plat->phy_interface is unsigned, so can't be negative and so the
comparison will always be false.
A possible fix is to use int variable ret for the assignment and check:
ret = device_get_phy_mode(&pdev->dev);
if (ret < 0)
dev_err(&pdev->dev, "phy_mode not found\n");
plat->phy_interface = ret;
..however, I think the dev_err may need handling too, e.g.
ret = device_get_phy_mode(&pdev->dev);
if (ret < 0) {
dev_err(&pdev->dev, "phy_mode not found\n");
ret = -ENODEV;
goto cleanup; /* needs to be written */
}
plat->phy_interface = ret;
Colin
On Mon, Jun 21, 2021 at 04:51:28PM +0100, Colin Ian King wrote:
Hi,
Static analysis by Coverity on today's linux-next has found an issue in
function loongson_dwmac_probe with the following commit:
commit 30bba69d7db40e732d6c0aa6d4890c60d717e314
Author: Qing Zhang [off-list ref]
Date: Fri Jun 18 10:53:34 2021 +0800
stmmac: pci: Add dwmac support for Loongson
The analysis is as follows:
110 plat->phy_interface = device_get_phy_mode(&pdev->dev);
Enum compared against 0
(NO_EFFECT)
unsigned_compare: This less-than-zero comparison of an
unsigned value is never true. plat->phy_interface < 0U.
111 if (plat->phy_interface < 0)
112 dev_err(&pdev->dev, "phy_mode not found\n");
Enum plat->phy_interface is unsigned, so can't be negative and so the
comparison will always be false.
A possible fix is to use int variable ret for the assignment and check:
ret = device_get_phy_mode(&pdev->dev);
if (ret < 0)
dev_err(&pdev->dev, "phy_mode not found\n");
plat->phy_interface = ret;
..however, I think the dev_err may need handling too, e.g.
ret = device_get_phy_mode(&pdev->dev);
if (ret < 0) {
dev_err(&pdev->dev, "phy_mode not found\n");
ret = -ENODEV;
goto cleanup; /* needs to be written */
}
plat->phy_interface = ret;
Potentially a cleaner fix is to use of_get_phy_mode(), which separates
the success/error value from the phy_interface_t.
Andrew
On 06/21/2021 11:51 PM, Colin Ian King wrote:
Hi,
Static analysis by Coverity on today's linux-next has found an issue in
function loongson_dwmac_probe with the following commit:
commit 30bba69d7db40e732d6c0aa6d4890c60d717e314
Author: Qing Zhang [off-list ref]
Date: Fri Jun 18 10:53:34 2021 +0800
stmmac: pci: Add dwmac support for Loongson
The analysis is as follows:
110 plat->phy_interface = device_get_phy_mode(&pdev->dev);
Enum compared against 0
(NO_EFFECT)
unsigned_compare: This less-than-zero comparison of an
unsigned value is never true. plat->phy_interface < 0U.
111 if (plat->phy_interface < 0)
112 dev_err(&pdev->dev, "phy_mode not found\n");
Enum plat->phy_interface is unsigned, so can't be negative and so the
comparison will always be false.
Hi，Colin
Thanks for your advice,
I see this judgment in stmmac_platform.c:
plat->phy_interface = device_get_phy_mode(&pdev->dev);
if (plat->phy_interface < 0)
return ERR_PTR(plat->phy_interface);
plat->interface = stmmac_of_get_mac_mode(np);
if (plat->interface < 0)
A possible fix is to use int variable ret for the assignment and check:
ret = device_get_phy_mode(&pdev->dev);
if (ret < 0)
dev_err(&pdev->dev, "phy_mode not found\n");
plat->phy_interface = ret;
..however, I think the dev_err may need handling too, e.g.
ret = device_get_phy_mode(&pdev->dev);
if (ret < 0) {
dev_err(&pdev->dev, "phy_mode not found\n");
ret = -ENODEV;
goto cleanup; /* needs to be written */
}
plat->phy_interface = ret;
Colin
looks ok, but can be written to use of_get_phy_mode() , like this:
phy_interface_t interface;
ret = of_get_phy_mode(pdev->dev->of_node, &interface);
if (ret)
return -EINVAL;
plat_dat->interface = interface;
if(!plat->interface)
dev_err(&pdev->dev, "Unsupported interface mode: %s",
phy_modes(plat->interface));
Thanks
-Qing