Subject: Re: [PATCH 1/2] net: dsa: ksz9477: add I2C managed mode support

From: Dan Carpenter <[email-masked]>
Date: Mon, 17 Dec 2018 09:54:55 +0300

On Sun, Dec 16, 2018 at 08:57:40AM +0100, Sergio Paracuellos wrote:
> +static int ksz_i2c_write(struct ksz_device *dev, u32 reg, u8 *val,
> +			 unsigned int len)
> +{
> +	struct i2c_client *client = dev->priv;
> +	unsigned int cnt = len;
> +	int i = 0;
> +	u8 txb[4];
> +
> +	do {
> +		txb[i++] = (u8)(*val >> (8 * (cnt - 1)));
                                              ^^^^^^^

Can "cnt" be zero from ksz_i2c_set()?  If so this loop will corrupt
memory.

> +		cnt--;
> +	} while (cnt);
> +
> +	return ksz_i2c_write_reg(client, reg, txb, len);
> +}
> +
> +static int ksz_i2c_write8(struct ksz_device *dev, u32 reg, u8 value)
> +{
> +	return ksz_i2c_write(dev, reg, &value, 1);
> +}
> +
> +static int ksz_i2c_write16(struct ksz_device *dev, u32 reg, u16 value)
> +{
> +	value = cpu_to_be16(value);
> +	return ksz_i2c_write(dev, reg, (u8 *)&value, 2);
> +}
> +
> +static int ksz_i2c_write24(struct ksz_device *dev, u32 reg, u32 value)
> +{
> +	/* make it to big endian 24bit from MSB */
> +	value <<= 8;
> +	value = cpu_to_be32(value);
> +
> +	return ksz_i2c_write(dev, reg, (u8 *)&value, 3);
> +}
> +
> +static int ksz_i2c_write32(struct ksz_device *dev, u32 reg, u32 value)
> +{
> +	value = cpu_to_be32(value);
> +	return ksz_i2c_write(dev, reg, (u8 *)&value, 4);
> +}
> +
> +static int ksz_i2c_get(struct ksz_device *dev, u32 reg, void *data, size_t len)
> +{
> +	return ksz_i2c_read(dev, reg, data, len);
> +}
> +
> +static int ksz_i2c_set(struct ksz_device *dev, u32 reg, void *data, size_t len)
> +{
> +	return ksz_i2c_write(dev, reg, data, len);
> +}
> +
> +static const struct ksz_io_ops ksz_i2c_ops = {
> +	.read8 = ksz_i2c_read8,
> +	.read16 = ksz_i2c_read16,
> +	.read24 = ksz_i2c_read24,
> +	.read32 = ksz_i2c_read32,
> +	.write8 = ksz_i2c_write8,
> +	.write16 = ksz_i2c_write16,
> +	.write24 = ksz_i2c_write24,
> +	.write32 = ksz_i2c_write32,
> +	.get = ksz_i2c_get,
> +	.set = ksz_i2c_set,
> +};
> +
> +static int ksz_i2c_probe(struct i2c_client *client,
> +			 const struct i2c_device_id *id)
> +{
> +	struct ksz_device *dev;
> +	int ret;
> +
> +	dev = ksz_switch_alloc(&client->dev, &ksz_i2c_ops, client);
> +	if (!dev)
> +		return -ENOMEM;
> +
> +	if (client->dev.platform_data)
> +		dev->pdata = client->dev.platform_data;
> +
> +	i2c_set_clientdata(client, dev);
> +
> +	ret = ksz9477_switch_register(dev);
> +	if (ret) {
> +		dev_err(&client->dev, "registering switch (ret: %d)\n", ret);

free dev on this error path?

> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +

regards,
dan carpenter