[PATCH -next] spi: stm32-qspi: Simpify resource lookup

[PATCH -next] spi: stm32-qspi: Simpify resource lookup

[Jinjie Ruan]

Use the devm_platform_ioremap_resource_byname() helper instead of
calling platform_get_resource_byname() and devm_ioremap_resource()
separately.

Signed-off-by: Jinjie Ruan <ruanjinjie@huawei.com>
---
 drivers/spi/spi-stm32-qspi.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/spi/spi-stm32-qspi.c b/drivers/spi/spi-stm32-qspi.c
index 955c920c4b63..46081df73cb0 100644
--- a/drivers/spi/spi-stm32-qspi.c
+++ b/drivers/spi/spi-stm32-qspi.c
@@ -780,15 +780,13 @@ static int stm32_qspi_probe(struct platform_device *pdev)
 	qspi = spi_controller_get_devdata(ctrl);
 	qspi->ctrl = ctrl;
 
-	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "qspi");
-	qspi->io_base = devm_ioremap_resource(dev, res);
+	qspi->io_base = devm_platform_ioremap_resource_byname(pdev, "qspi");
 	if (IS_ERR(qspi->io_base))
 		return PTR_ERR(qspi->io_base);
 
 	qspi->phys_base = res->start;
 
-	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "qspi_mm");
-	qspi->mm_base = devm_ioremap_resource(dev, res);
+	qspi->mm_base = devm_platform_ioremap_resource_byname(pdev, "qspi_mm");
 	if (IS_ERR(qspi->mm_base))
 		return PTR_ERR(qspi->mm_base);
 
-- 
2.34.1

Re: [PATCH -next] spi: stm32-qspi: Simpify resource lookup

[Mark Brown]

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On Tue, Aug 20, 2024 at 08:37:07PM +0800, Jinjie Ruan wrote:
> Use the devm_platform_ioremap_resource_byname() helper instead of
> calling platform_get_resource_byname() and devm_ioremap_resource()
> separately.

This breaks boot on the Avenger96 board, it causes a NULL pointer
dereference:

[    2.350480] Unable to handle kernel NULL pointer dereference at virtual address 00000000 when read

...

[    2.695787] Call trace:
[    2.695807]  stm32_qspi_probe from platform_probe+0x5c/0xb0
[    2.703914]  platform_probe from really_probe+0xc8/0x2c8
[    2.709284]  really_probe from __driver_probe_device+0x88/0x19c
[    2.715145]  __driver_probe_device from driver_probe_device+0x30/0x104

https://lava.sirena.org.uk/scheduler/job/650792

> -	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "qspi");
> -	qspi->io_base = devm_ioremap_resource(dev, res);
> +	qspi->io_base = devm_platform_ioremap_resource_byname(pdev, "qspi");
>  	if (IS_ERR(qspi->io_base))
>  		return PTR_ERR(qspi->io_base);
>  
>  	qspi->phys_base = res->start;
>  
> -	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "qspi_mm");
> -	qspi->mm_base = devm_ioremap_resource(dev, res);
> +	qspi->mm_base = devm_platform_ioremap_resource_byname(pdev, "qspi_mm");
>  	if (IS_ERR(qspi->mm_base))
>  		return PTR_ERR(qspi->mm_base);

I can't identify any obvious error here, these look like a direct
subsitution - the implementation of devm_platform_ioremap_resource_byname()
looks to be the same as the replaced code and dev is set to &pdev->dev
but I'm seeing the above behaviour.

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Re: [PATCH -next] spi: stm32-qspi: Simpify resource lookup

[Jinjie Ruan]

On 2024/8/22 22:58, Mark Brown wrote:
> On Tue, Aug 20, 2024 at 08:37:07PM +0800, Jinjie Ruan wrote:
>> Use the devm_platform_ioremap_resource_byname() helper instead of
>> calling platform_get_resource_byname() and devm_ioremap_resource()
>> separately.
> 
> This breaks boot on the Avenger96 board, it causes a NULL pointer
> dereference:
> 
> [    2.350480] Unable to handle kernel NULL pointer dereference at virtual address 00000000 when read
> 
> ...
> 
> [    2.695787] Call trace:
> [    2.695807]  stm32_qspi_probe from platform_probe+0x5c/0xb0
> [    2.703914]  platform_probe from really_probe+0xc8/0x2c8
> [    2.709284]  really_probe from __driver_probe_device+0x88/0x19c
> [    2.715145]  __driver_probe_device from driver_probe_device+0x30/0x104
> 
> https://lava.sirena.org.uk/scheduler/job/650792
> 
>> -	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "qspi");
>> -	qspi->io_base = devm_ioremap_resource(dev, res);
>> +	qspi->io_base = devm_platform_ioremap_resource_byname(pdev, "qspi");
>>  	if (IS_ERR(qspi->io_base))
>>  		return PTR_ERR(qspi->io_base);
>>  
>>  	qspi->phys_base = res->start;
>>  
>> -	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "qspi_mm");
>> -	qspi->mm_base = devm_ioremap_resource(dev, res);
>> +	qspi->mm_base = devm_platform_ioremap_resource_byname(pdev, "qspi_mm");
>>  	if (IS_ERR(qspi->mm_base))
>>  		return PTR_ERR(qspi->mm_base);
> 
> I can't identify any obvious error here, these look like a direct
> subsitution - the implementation of devm_platform_ioremap_resource_byname()
> looks to be the same as the replaced code and dev is set to &pdev->dev
> but I'm seeing the above behaviour.

Mark, thank you very much, I can't identify the error here too. This bug
may be easy to locate if have a reproduction environment, but it's good
to keep it the way it is.

Re: [PATCH -next] spi: stm32-qspi: Simpify resource lookup

[Jinjie Ruan]

On 2024/8/22 22:58, Mark Brown wrote:
> On Tue, Aug 20, 2024 at 08:37:07PM +0800, Jinjie Ruan wrote:
>> Use the devm_platform_ioremap_resource_byname() helper instead of
>> calling platform_get_resource_byname() and devm_ioremap_resource()
>> separately.
> 
> This breaks boot on the Avenger96 board, it causes a NULL pointer
> dereference:
> 
> [    2.350480] Unable to handle kernel NULL pointer dereference at virtual address 00000000 when read
> 
> ...
> 
> [    2.695787] Call trace:
> [    2.695807]  stm32_qspi_probe from platform_probe+0x5c/0xb0
> [    2.703914]  platform_probe from really_probe+0xc8/0x2c8
> [    2.709284]  really_probe from __driver_probe_device+0x88/0x19c
> [    2.715145]  __driver_probe_device from driver_probe_device+0x30/0x104
> 
> https://lava.sirena.org.uk/scheduler/job/650792
> 
>> -	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "qspi");
>> -	qspi->io_base = devm_ioremap_resource(dev, res);
>> +	qspi->io_base = devm_platform_ioremap_resource_byname(pdev, "qspi");
>>  	if (IS_ERR(qspi->io_base))
>>  		return PTR_ERR(qspi->io_base);
>>  
>>  	qspi->phys_base = res->start;
>>  
>> -	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "qspi_mm");
>> -	qspi->mm_base = devm_ioremap_resource(dev, res);
>> +	qspi->mm_base = devm_platform_ioremap_resource_byname(pdev, "qspi_mm");
>>  	if (IS_ERR(qspi->mm_base))
>>  		return PTR_ERR(qspi->mm_base);
> 
> I can't identify any obvious error here, these look like a direct
> subsitution - the implementation of devm_platform_ioremap_resource_byname()
> looks to be the same as the replaced code and dev is set to &pdev->dev
> but I'm seeing the above behaviour.

Sorry, from lkp@intel.com，I identify that the "res" returned by
platform_get_resource_byname() is used by "qspi->phys_base =
res->start;" later，so the devm_platform_ioremap_resource_byname() is not
inapplicable here.