Re:Re:RE: [PATCH] pinctrl: mcp23s08: reject devices without match data

[jiale yao]

At 2026-09-26 18:23:42, "jiale yao" <19888972804@xxxxxxx> wrote:
>Hi Biju,
>
>At 2026-09-26 18:07:14, "Biju Das" <biju.das.jz@xxxxxxxxxxxxxx> wrote:
>>Hi,
>>
>>> -----Original Message-----
>>> From: Jiale Yao <yaojiale02@xxxxxxx>
>>> Sent: 25 September 2026 14:38
>>> Subject: [PATCH] pinctrl: mcp23s08: reject devices without match data
>>> 
>>> A device bound through driver_override need not match an entry in the driver tables. In that case
>>> spi_get_device_match_data() returns NULL, but mcp23s08_probe() later passes the result to the regmap
>>> setup and dereferences it while setting up each device.
>>
>>I believe this is an invalid use case as the user trying driver_override
>>and the probe returns error. Am I missing anything here?
>
>Yes, my commit message was not clear enough. This patch is intended to fix
>a regression introduced by commit 2e44555b05c0, rather than to make an
>unmatched device probe successfully through driver_override.
>
>Before that commit, missing match data effectively resulted in type 0,
>which fell through to the default switch case and returned -EINVAL.
>Commit 2e44555b05c0 replaced the type value with an info pointer, but the
>SPI path missed the corresponding NULL check before dereferencing
>info->type. The I2C path preserved the previous error handling with an
>explicit NULL check after the same conversion.

Just like.
---
+       info = i2c_get_match_data(client);
+       if (!info)
+               return dev_err_probe(dev, -EINVAL, "invalid device type\n");
---
The return value of spi_get_device_match_data should be check also.

>
>Consequently, an unmatched device bound through driver_override used to
>fail cleanly. It can now cause a NULL pointer dereference when a valid
>spi-present-mask property is present. This patch restores the previous
>failure behavior.
>
>>
>>Can you please prepare a patch that makes the driver probe success by using driver_override
>>Feature? Also please share some logs to see how it works in real device
>>
>>Cheers,
>>Biju
>>
>>> 
>>> Reject devices without match data before reading device properties.
>>> 
>>> Fixes: 2e44555b05c0 ("pinctrl: mcp23s08: Simplify probe()/mcp23s08_spi_regmap_init()")
>>> Signed-off-by: Jiale Yao <yaojiale02@xxxxxxx>
>>> ---
>>>  drivers/pinctrl/pinctrl-mcp23s08_spi.c | 2 ++
>>>  1 file changed, 2 insertions(+)
>>> 
>>> diff --git a/drivers/pinctrl/pinctrl-mcp23s08_spi.c b/drivers/pinctrl/pinctrl-mcp23s08_spi.c
>>> index bacebcff67ef..926034fcd512 100644
>>> --- a/drivers/pinctrl/pinctrl-mcp23s08_spi.c
>>> +++ b/drivers/pinctrl/pinctrl-mcp23s08_spi.c
>>> @@ -146,6 +146,8 @@ static int mcp23s08_probe(struct spi_device *spi)
>>>  	u8 v;
>>> 
>>>  	info = spi_get_device_match_data(spi);
>>> +	if (!info)
>>> +		return -ENODATA;
>>> 
>>>  	ret = device_property_read_u8(dev, "microchip,spi-present-mask", &v);
>>>  	if (ret) {
>>> --
>>> 2.34.1
>
>Cheers,
>Jiale
>