diff mbox series

[-next,2/2] spi: microchip-core: switch to use devm_spi_alloc_master()

Message ID 20220712135357.918997-2-yangyingliang@huawei.com
State Superseded
Headers show
Series [-next,1/2] spi: microchip-core: fix UAF in mchp_corespi_remove() | expand

Commit Message

Yang Yingliang July 12, 2022, 1:53 p.m. UTC
Switch to use devm_spi_alloc_master() to simpify error path.

Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
---
 drivers/spi/spi-microchip-core.c | 20 +++++++-------------
 1 file changed, 7 insertions(+), 13 deletions(-)

Comments

Conor Dooley July 12, 2022, 2:03 p.m. UTC | #1
On 12/07/2022 14:53, Yang Yingliang wrote:
> [Some people who received this message don't often get email from yangyingliang@huawei.com. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ]
> 
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> Switch to use devm_spi_alloc_master() to simpify error path.

Hey Yang,
Thanks for trying to fix my mistakes!

Forgive my innocence here, but why is it okay to remove the
spi_master_put() in remove() but not the one in the error path of
the probe function?

If the devm_add_action_or_reset() in devm_spi_register_controller()
fails won't the same thing apply to the probe error path?

IOW, I think this patch needs a fixes tag too b/c it also fixes a
refcount underflow. Please correct me if I am misunderstanding.

One other comment below.

> 
> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
> ---
>   drivers/spi/spi-microchip-core.c | 20 +++++++-------------
>   1 file changed, 7 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/spi/spi-microchip-core.c b/drivers/spi/spi-microchip-core.c
> index c26767343176..1a24e47f8305 100644
> --- a/drivers/spi/spi-microchip-core.c
> +++ b/drivers/spi/spi-microchip-core.c
> @@ -513,7 +513,7 @@ static int mchp_corespi_probe(struct platform_device *pdev)
>          u32 num_cs;
>          int ret = 0;
> 
> -       master = spi_alloc_master(&pdev->dev, sizeof(*spi));
> +       master = devm_spi_alloc_master(&pdev->dev, sizeof(*spi));
>          if (!master)
>                  return dev_err_probe(&pdev->dev, -ENOMEM,
>                                       "unable to allocate master for SPI controller\n");
> @@ -535,36 +535,32 @@ static int mchp_corespi_probe(struct platform_device *pdev)
>          spi = spi_master_get_devdata(master);
> 
>          spi->regs = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
> -       if (IS_ERR(spi->regs)) {
> -               ret = PTR_ERR(spi->regs);
> -               goto error_release_master;
> -       }
> +       if (IS_ERR(spi->regs))
> +               return PTR_ERR(spi->regs);
> 
>          spi->irq = platform_get_irq(pdev, 0);
>          if (spi->irq <= 0) {
>                  dev_err(&pdev->dev, "invalid IRQ %d for SPI controller\n", spi->irq);
> -               ret = -ENXIO;
> -               goto error_release_master;
> +               return -ENXIO;

Also these can now become dev_err_probe for further simplification?
Thanks,
Conor.

>          }
> 
>          ret = devm_request_irq(&pdev->dev, spi->irq, mchp_corespi_interrupt,
>                                 IRQF_SHARED, dev_name(&pdev->dev), master);
>          if (ret) {
>                  dev_err(&pdev->dev, "could not request irq: %d\n", ret);
> -               goto error_release_master;
> +               return ret;
>          }
> 
>          spi->clk = devm_clk_get(&pdev->dev, NULL);
>          if (IS_ERR(spi->clk)) {
> -               ret = PTR_ERR(spi->clk);
>                  dev_err(&pdev->dev, "could not get clk: %d\n", ret);
> -               goto error_release_master;
> +               return PTR_ERR(spi->clk);
>          }
> 
>          ret = clk_prepare_enable(spi->clk);
>          if (ret) {
>                  dev_err(&pdev->dev, "failed to enable clock\n");
> -               goto error_release_master;
> +               return ret;
>          }
> 
>          mchp_corespi_init(master, spi);
> @@ -583,8 +579,6 @@ static int mchp_corespi_probe(struct platform_device *pdev)
>   error_release_hardware:
>          mchp_corespi_disable(spi);
>          clk_disable_unprepare(spi->clk);
> -error_release_master:
> -       spi_master_put(master);
> 
>          return ret;
>   }
> --
> 2.25.1
>
Conor Dooley July 12, 2022, 8:50 p.m. UTC | #2
On 12/07/2022 15:03, Conor.Dooley@microchip.com wrote:
> On 12/07/2022 14:53, Yang Yingliang wrote:
>> [Some people who received this message don't often get email from yangyingliang@huawei.com. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ]
>>
>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>>
>> Switch to use devm_spi_alloc_master() to simpify error path.
> 
> Hey Yang,
> Thanks for trying to fix my mistakes!
> 
> Forgive my innocence here, but why is it okay to remove the
> spi_master_put() in remove() but not the one in the error path of
> the probe function?
> 
> If the devm_add_action_or_reset() in devm_spi_register_controller()
> fails won't the same thing apply to the probe error path?
> 
> IOW, I think this patch needs a fixes tag too b/c it also fixes a
> refcount underflow. Please correct me if I am misunderstanding.

Ahh, I just saw your revert of 59ebbe40fb51 ("spi: simplify
devm_spi register_controller"). With that, this makes a lot more
sense.

> 
> One other comment below.

This comment still applies for this patch. dev_err_probe would be
nice.

Thanks,
Conor.

> 
>>
>> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
>> ---
>>   drivers/spi/spi-microchip-core.c | 20 +++++++-------------
>>   1 file changed, 7 insertions(+), 13 deletions(-)
>>
>> diff --git a/drivers/spi/spi-microchip-core.c b/drivers/spi/spi-microchip-core.c
>> index c26767343176..1a24e47f8305 100644
>> --- a/drivers/spi/spi-microchip-core.c
>> +++ b/drivers/spi/spi-microchip-core.c
>> @@ -513,7 +513,7 @@ static int mchp_corespi_probe(struct platform_device *pdev)
>>          u32 num_cs;
>>          int ret = 0;
>>
>> -       master = spi_alloc_master(&pdev->dev, sizeof(*spi));
>> +       master = devm_spi_alloc_master(&pdev->dev, sizeof(*spi));
>>          if (!master)
>>                  return dev_err_probe(&pdev->dev, -ENOMEM,
>>                                       "unable to allocate master for SPI controller\n");
>> @@ -535,36 +535,32 @@ static int mchp_corespi_probe(struct platform_device *pdev)
>>          spi = spi_master_get_devdata(master);
>>
>>          spi->regs = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
>> -       if (IS_ERR(spi->regs)) {
>> -               ret = PTR_ERR(spi->regs);
>> -               goto error_release_master;
>> -       }
>> +       if (IS_ERR(spi->regs))
>> +               return PTR_ERR(spi->regs);
>>
>>          spi->irq = platform_get_irq(pdev, 0);
>>          if (spi->irq <= 0) {
>>                  dev_err(&pdev->dev, "invalid IRQ %d for SPI controller\n", spi->irq);
>> -               ret = -ENXIO;
>> -               goto error_release_master;
>> +               return -ENXIO;
> 
> Also these can now become dev_err_probe for further simplification?
> Thanks,
> Conor.
> 
>>          }
>>
>>          ret = devm_request_irq(&pdev->dev, spi->irq, mchp_corespi_interrupt,
>>                                 IRQF_SHARED, dev_name(&pdev->dev), master);
>>          if (ret) {
>>                  dev_err(&pdev->dev, "could not request irq: %d\n", ret);
>> -               goto error_release_master;
>> +               return ret;
>>          }
>>
>>          spi->clk = devm_clk_get(&pdev->dev, NULL);
>>          if (IS_ERR(spi->clk)) {
>> -               ret = PTR_ERR(spi->clk);
>>                  dev_err(&pdev->dev, "could not get clk: %d\n", ret);
>> -               goto error_release_master;
>> +               return PTR_ERR(spi->clk);
>>          }
>>
>>          ret = clk_prepare_enable(spi->clk);
>>          if (ret) {
>>                  dev_err(&pdev->dev, "failed to enable clock\n");
>> -               goto error_release_master;
>> +               return ret;
>>          }
>>
>>          mchp_corespi_init(master, spi);
>> @@ -583,8 +579,6 @@ static int mchp_corespi_probe(struct platform_device *pdev)
>>   error_release_hardware:
>>          mchp_corespi_disable(spi);
>>          clk_disable_unprepare(spi->clk);
>> -error_release_master:
>> -       spi_master_put(master);
>>
>>          return ret;
>>   }
>> --
>> 2.25.1
>>
> 
> _______________________________________________
> linux-riscv mailing list
> linux-riscv@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-riscv
Yang Yingliang July 13, 2022, 2:14 a.m. UTC | #3
On 2022/7/13 4:50, Conor.Dooley@microchip.com wrote:
> On 12/07/2022 15:03, Conor.Dooley@microchip.com wrote:
>> On 12/07/2022 14:53, Yang Yingliang wrote:
>>> [Some people who received this message don't often get email from yangyingliang@huawei.com. Learn why this is important at https://aka.ms/LearnAboutSenderIdentification ]
>>>
>>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>>>
>>> Switch to use devm_spi_alloc_master() to simpify error path.
>> Hey Yang,
>> Thanks for trying to fix my mistakes!
>>
>> Forgive my innocence here, but why is it okay to remove the
>> spi_master_put() in remove() but not the one in the error path of
>> the probe function?
>>
>> If the devm_add_action_or_reset() in devm_spi_register_controller()
>> fails won't the same thing apply to the probe error path?
>>
>> IOW, I think this patch needs a fixes tag too b/c it also fixes a
>> refcount underflow. Please correct me if I am misunderstanding.
> Ahh, I just saw your revert of 59ebbe40fb51 ("spi: simplify
> devm_spi register_controller"). With that, this makes a lot more
> sense.
>
>> One other comment below.
> This comment still applies for this patch. dev_err_probe would be
> nice.
OK.

Thanks,
Yang
>
> Thanks,
> Conor.
diff mbox series

Patch

diff --git a/drivers/spi/spi-microchip-core.c b/drivers/spi/spi-microchip-core.c
index c26767343176..1a24e47f8305 100644
--- a/drivers/spi/spi-microchip-core.c
+++ b/drivers/spi/spi-microchip-core.c
@@ -513,7 +513,7 @@  static int mchp_corespi_probe(struct platform_device *pdev)
 	u32 num_cs;
 	int ret = 0;
 
-	master = spi_alloc_master(&pdev->dev, sizeof(*spi));
+	master = devm_spi_alloc_master(&pdev->dev, sizeof(*spi));
 	if (!master)
 		return dev_err_probe(&pdev->dev, -ENOMEM,
 				     "unable to allocate master for SPI controller\n");
@@ -535,36 +535,32 @@  static int mchp_corespi_probe(struct platform_device *pdev)
 	spi = spi_master_get_devdata(master);
 
 	spi->regs = devm_platform_get_and_ioremap_resource(pdev, 0, &res);
-	if (IS_ERR(spi->regs)) {
-		ret = PTR_ERR(spi->regs);
-		goto error_release_master;
-	}
+	if (IS_ERR(spi->regs))
+		return PTR_ERR(spi->regs);
 
 	spi->irq = platform_get_irq(pdev, 0);
 	if (spi->irq <= 0) {
 		dev_err(&pdev->dev, "invalid IRQ %d for SPI controller\n", spi->irq);
-		ret = -ENXIO;
-		goto error_release_master;
+		return -ENXIO;
 	}
 
 	ret = devm_request_irq(&pdev->dev, spi->irq, mchp_corespi_interrupt,
 			       IRQF_SHARED, dev_name(&pdev->dev), master);
 	if (ret) {
 		dev_err(&pdev->dev, "could not request irq: %d\n", ret);
-		goto error_release_master;
+		return ret;
 	}
 
 	spi->clk = devm_clk_get(&pdev->dev, NULL);
 	if (IS_ERR(spi->clk)) {
-		ret = PTR_ERR(spi->clk);
 		dev_err(&pdev->dev, "could not get clk: %d\n", ret);
-		goto error_release_master;
+		return PTR_ERR(spi->clk);
 	}
 
 	ret = clk_prepare_enable(spi->clk);
 	if (ret) {
 		dev_err(&pdev->dev, "failed to enable clock\n");
-		goto error_release_master;
+		return ret;
 	}
 
 	mchp_corespi_init(master, spi);
@@ -583,8 +579,6 @@  static int mchp_corespi_probe(struct platform_device *pdev)
 error_release_hardware:
 	mchp_corespi_disable(spi);
 	clk_disable_unprepare(spi->clk);
-error_release_master:
-	spi_master_put(master);
 
 	return ret;
 }