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SubjectRe: [PATCH v4] i2c: busses: i2c-pxa.c: Fix for possible null pointer dereference
2014-08-02 13:30 GMT+02:00 Wolfram Sang <wsa@the-dreams.de>:
> Hi,
>
>> res = platform_get_resource(dev, IORESOURCE_MEM, 0);
>> irq = platform_get_irq(dev, 0);
>> - if (res == NULL || irq < 0) {
>> - ret = -ENODEV;
>> - goto eclk;
>> - }
>> + if (res == NULL || irq < 0)
>> + return -ENODEV;
>
> No need to check for valid 'res' here...
>
>>
>> - if (!request_mem_region(res->start, resource_size(res), res->name)) {
>> - ret = -ENOMEM;
>> - goto eclk;
>> - }
>> + if (!devm_request_mem_region(&dev->dev, res->start,
>> + resource_size(res), res->name))
>> + return -ENOMEM;
>
> ... and no need to use 'devm_request_mem_region' ...
>
>> - i2c->reg_base = ioremap(res->start, resource_size(res));
>> - if (!i2c->reg_base) {
>> - ret = -EIO;
>> - goto eremap;
>> - }
>> + i2c->reg_base = devm_ioremap_resource(&adev->dev, res));
>> + if (IS_ERR(i2c->reg_base))
>> + return -EIO;
>
> ... because devm_ioremap_resource does all that for you. Also, don't
> return -EIO but the PTR_ERR given from the function. Just check other
> drivers how they do it.
>
>>
>> i2c->reg_ibmr = i2c->reg_base + pxa_reg_layout[i2c_type].ibmr;
>> i2c->reg_idbr = i2c->reg_base + pxa_reg_layout[i2c_type].idbr;
>> @@ -1227,10 +1218,12 @@ static int i2c_pxa_probe(struct platform_device *dev)
>> i2c->adap.algo = &i2c_pxa_pio_algorithm;
>> } else {
>> i2c->adap.algo = &i2c_pxa_algorithm;
>> - ret = request_irq(irq, i2c_pxa_handler, IRQF_SHARED,
>> - dev_name(&dev->dev), i2c);
>> - if (ret)
>> - goto ereqirq;
>> + ret = devm_request_irq(&dev->dev, irq, i2c_pxa_handler,
>> + IRQF_SHARED, dev_name(&dev->dev), i2c);
>> + if (ret) {
>> + clk_disable_unprepare(i2c->clk);
>> + return ret;
>
> Maybe you should make a error path with 'goto' out of it...
>
>
>> + }
>> }
>>
>> i2c_pxa_reset(i2c);
>> @@ -1244,7 +1237,7 @@ static int i2c_pxa_probe(struct platform_device *dev)
>> ret = i2c_add_numbered_adapter(&i2c->adap);
>> if (ret < 0) {
>> printk(KERN_INFO "I2C: Failed to add bus\n");
>> - goto eadapt;
>> + return ret;
>
> ... since you forgot disable_unprepare here and could simply reuse it.
>
>
>> }
>>
>> platform_set_drvdata(dev, i2c);
>> @@ -1257,20 +1250,6 @@ static int i2c_pxa_probe(struct platform_device *dev)
>> dev_name(&i2c->adap.dev));
>> #endif
>> return 0;
>> -
>> -eadapt:
>> - if (!i2c->use_pio)
>> - free_irq(irq, i2c);
>> -ereqirq:
>> - clk_disable_unprepare(i2c->clk);
>> - iounmap(i2c->reg_base);
>> -eremap:
>> - clk_put(i2c->clk);
>> -eclk:
>> - kfree(i2c);
>> -emalloc:
>> - release_mem_region(res->start, resource_size(res));
>> - return ret;
>> }
>
> You forgot to cleanup the remove function.
>
> BTW I forgot, can you test this patch on real hardware? If not, is there
> somebody who does?
>
> All the best,
>
> Wolfram



Hi

I have made a lot of changes on changes to changes, and have really
tried to ensure that all would be right.

But I feel like that's enough, Wolfram or anyone else may end this.

And no as I replied earlier, I lack this kind of hardware...


Kind regards
Rickard Strandqvist


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