When devm_kasprintf() fails, it returns a NULL pointer. However, this return value is not properly checked in the function uio_fsl_elbc_gpcm_probe.

A NULL check should be added after the devm_kasprintf() to prevent potential NULL pointer dereference error.

Fixes: d57801c45f53e ("uio: uio_fsl_elbc_gpcm: use device-managed allocators")

Signed-off-by: Henry Martin <bsdhenrymartin@gmail.com>
---
 drivers/uio/uio_fsl_elbc_gpcm.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/uio/uio_fsl_elbc_gpcm.c b/drivers/uio/uio_fsl_elbc_gpcm.c
index 81454c3e2484..59ba1a2dcfe3 100644
--- a/drivers/uio/uio_fsl_elbc_gpcm.c
+++ b/drivers/uio/uio_fsl_elbc_gpcm.c
@@ -384,6 +384,10 @@ static int uio_fsl_elbc_gpcm_probe(struct platform_device *pdev)
 
 	/* set all UIO data */
 	info->mem[0].name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%pOFn", node);
+	if (!info->mem[0].name) {
+		dev_err(priv->dev, "devm_kasprintf failed for region name\n");
+		return -ENOMEM;
+	}
 	info->mem[0].addr = res.start;
 	info->mem[0].size = resource_size(&res);
 	info->mem[0].memtype = UIO_MEM_PHYS;
-- 
2.34.1

On 31/03/2025 11:27, Henry Martin wrote:
> When devm_kasprintf() fails, it returns a NULL pointer. However, this return value is not properly checked in the function uio_fsl_elbc_gpcm_probe.
> 
> A NULL check should be added after the devm_kasprintf() to prevent potential NULL pointer dereference error.
> 
> Fixes: d57801c45f53e ("uio: uio_fsl_elbc_gpcm: use device-managed allocators")
> 


Same comments as for other patches.

> Signed-off-by: Henry Martin <bsdhenrymartin@gmail.com>
> ---
>  drivers/uio/uio_fsl_elbc_gpcm.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/uio/uio_fsl_elbc_gpcm.c b/drivers/uio/uio_fsl_elbc_gpcm.c
> index 81454c3e2484..59ba1a2dcfe3 100644
> --- a/drivers/uio/uio_fsl_elbc_gpcm.c
> +++ b/drivers/uio/uio_fsl_elbc_gpcm.c
> @@ -384,6 +384,10 @@ static int uio_fsl_elbc_gpcm_probe(struct platform_device *pdev)
>  
>  	/* set all UIO data */
>  	info->mem[0].name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%pOFn", node);
> +	if (!info->mem[0].name) {
> +		dev_err(priv->dev, "devm_kasprintf failed for region name\n");


There is never a printk after memory allocation failure.

Also, just like in some of the other patches, you did not really analyze
the code - you leak here resource map. Just look at the entire code
instead of blindly pasting the same code here and there.

Best regards,
Krzysztof

devm_kasprintf() returns NULL when memory allocation fails. Currently,
uio_fsl_elbc_gpcm_probe() does not check for this case, which results in
a NULL pointer dereference.

Add NULL check after devm_kasprintf() to prevent this issue and ensuring
no resources are left allocated.

Fixes: d57801c45f53 ("uio: uio_fsl_elbc_gpcm: use device-managed allocators")
Signed-off-by: Henry Martin <bsdhenrymartin@gmail.com>
---
V1 -> V2: Remove printk after memory failure and add proper resource
cleanup.

 drivers/uio/uio_fsl_elbc_gpcm.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/uio/uio_fsl_elbc_gpcm.c b/drivers/uio/uio_fsl_elbc_gpcm.c
index 81454c3e2484..26be556d956c 100644
--- a/drivers/uio/uio_fsl_elbc_gpcm.c
+++ b/drivers/uio/uio_fsl_elbc_gpcm.c
@@ -384,6 +384,10 @@ static int uio_fsl_elbc_gpcm_probe(struct platform_device *pdev)
 
 	/* set all UIO data */
 	info->mem[0].name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%pOFn", node);
+	if (!info->mem[0].name) {
+		ret = -ENOMEM;
+		goto out_err3;
+	}
 	info->mem[0].addr = res.start;
 	info->mem[0].size = resource_size(&res);
 	info->mem[0].memtype = UIO_MEM_PHYS;
@@ -423,6 +427,7 @@ static int uio_fsl_elbc_gpcm_probe(struct platform_device *pdev)
 out_err2:
 	if (priv->shutdown)
 		priv->shutdown(info, true);
+out_err3:
 	iounmap(info->mem[0].internal_addr);
 	return ret;
 }
-- 
2.34.1

On Tue, Apr 01, 2025 at 06:02:40PM +0800, Henry Martin wrote:
> devm_kasprintf() returns NULL when memory allocation fails. Currently,
> uio_fsl_elbc_gpcm_probe() does not check for this case, which results in
> a NULL pointer dereference.
> 
> Add NULL check after devm_kasprintf() to prevent this issue and ensuring
> no resources are left allocated.
> 
> Fixes: d57801c45f53 ("uio: uio_fsl_elbc_gpcm: use device-managed allocators")
> Signed-off-by: Henry Martin <bsdhenrymartin@gmail.com>
> ---
> V1 -> V2: Remove printk after memory failure and add proper resource
> cleanup.
> 
>  drivers/uio/uio_fsl_elbc_gpcm.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/uio/uio_fsl_elbc_gpcm.c b/drivers/uio/uio_fsl_elbc_gpcm.c
> index 81454c3e2484..26be556d956c 100644
> --- a/drivers/uio/uio_fsl_elbc_gpcm.c
> +++ b/drivers/uio/uio_fsl_elbc_gpcm.c
> @@ -384,6 +384,10 @@ static int uio_fsl_elbc_gpcm_probe(struct platform_device *pdev)
>  
>  	/* set all UIO data */
>  	info->mem[0].name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "%pOFn", node);
> +	if (!info->mem[0].name) {
> +		ret = -ENOMEM;
> +		goto out_err3;
> +	}
>  	info->mem[0].addr = res.start;
>  	info->mem[0].size = resource_size(&res);
>  	info->mem[0].memtype = UIO_MEM_PHYS;
> @@ -423,6 +427,7 @@ static int uio_fsl_elbc_gpcm_probe(struct platform_device *pdev)
>  out_err2:
>  	if (priv->shutdown)
>  		priv->shutdown(info, true);
> +out_err3:
>  	iounmap(info->mem[0].internal_addr);
>  	return ret;
>  }
> -- 
> 2.34.1
> 

Hi,

This is the friendly patch-bot of Greg Kroah-Hartman.  You have sent him
a patch that has triggered this response.  He used to manually respond
to these common problems, but in order to save his sanity (he kept
writing the same thing over and over, yet to different people), I was
created.  Hopefully you will not take offence and will fix the problem
in your patch and resubmit it so that it can be accepted into the Linux
kernel tree.

You are receiving this message because of the following common error(s)
as indicated below:

- You have marked a patch with a "Fixes:" tag for a commit that is in an
  older released kernel, yet you do not have a cc: stable line in the
  signed-off-by area at all, which means that the patch will not be
  applied to any older kernel releases.  To properly fix this, please
  follow the documented rules in the
  Documentation/process/stable-kernel-rules.rst file for how to resolve
  this.

If you wish to discuss this problem further, or you have questions about
how to resolve this issue, please feel free to respond to this email and
Greg will reply once he has dug out from the pending patches received
from other developers.

thanks,

greg k-h's patch email bot