[PATCH] phy: mdio_bus: Check ENOTSUPP instead of ENOSYS in mdiobus_register_reset

[PATCH] phy: mdio_bus: Check ENOTSUPP instead of ENOSYS in mdiobus_register_reset

[Michal Simek]

Origin patch was using ENOTSUPP instead of ENOSYS. Silently changing error
value ends up in an access to bad area on Microblaze with axi ethernet
driver.

Fixes: 1d4639567d97 ("mdio_bus: Fix PTR_ERR applied after initialization to constant")
Signed-off-by: Michal Simek <michal.simek@xilinx.com>
---

I didn't track it down where exactly that access happens but the patch is
clearly just changing something without description.

The origin patch has been merged between rc7 and rc8 and would be good to
get this fix to v5.4.
---
 drivers/net/phy/mdio_bus.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index 35876562e32a..dbacb0031877 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c
@@ -65,7 +65,7 @@ static int mdiobus_register_reset(struct mdio_device *mdiodev)
 		reset = devm_reset_control_get_exclusive(&mdiodev->dev,
 							 "phy");
 	if (IS_ERR(reset)) {
-		if (PTR_ERR(reset) == -ENOENT || PTR_ERR(reset) == -ENOSYS)
+		if (PTR_ERR(reset) == -ENOENT || PTR_ERR(reset) == -ENOTSUPP)
 			reset = NULL;
 		else
 			return PTR_ERR(reset);
-- 
2.17.1

Re: [PATCH] phy: mdio_bus: Check ENOTSUPP instead of ENOSYS in mdiobus_register_reset

[Florian Fainelli]

On 11/19/19 5:27 AM, Michal Simek wrote:
> Origin patch was using ENOTSUPP instead of ENOSYS. Silently changing error
> value ends up in an access to bad area on Microblaze with axi ethernet
> driver.
> 
> Fixes: 1d4639567d97 ("mdio_bus: Fix PTR_ERR applied after initialization to constant")
> Signed-off-by: Michal Simek <michal.simek@xilinx.com>

This has been fixed in the "net" tree already:

https://git.kernel.org/pub/scm/linux/kernel/git/davem/net.git/commit/?id=075e238d12c21c8bde700d21fb48be7a3aa80194
-- 
Florian

Re: [PATCH] phy: mdio_bus: Check ENOTSUPP instead of ENOSYS in mdiobus_register_reset

[Michal Simek]

On 19. 11. 19 19:04, Florian Fainelli wrote:
> On 11/19/19 5:27 AM, Michal Simek wrote:
>> Origin patch was using ENOTSUPP instead of ENOSYS. Silently changing error
>> value ends up in an access to bad area on Microblaze with axi ethernet
>> driver.
>>
>> Fixes: 1d4639567d97 ("mdio_bus: Fix PTR_ERR applied after initialization to constant")
>> Signed-off-by: Michal Simek <michal.simek@xilinx.com>
> 
> This has been fixed in the "net" tree already:
> 
> https://git.kernel.org/pub/scm/linux/kernel/git/davem/net.git/commit/?id=075e238d12c21c8bde700d21fb48be7a3aa80194
> 

Works for me.

Thanks,
Michal