devm_kasprintf() can return a NULL pointer on failure,but this
returned value in tps6594_pfsm_probe() is not checked.
Add NULL check in tps6594_pfsm_probe(), to handle kernel NULL
pointer dereference error.

Fixes: a0df3ef087f8 ("misc: tps6594-pfsm: Add driver for TI TPS6594 PFSM")
Signed-off-by: Charles Han <hanchunchao@inspur.com>
---
 drivers/misc/tps6594-pfsm.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/misc/tps6594-pfsm.c b/drivers/misc/tps6594-pfsm.c
index 0a24ce44cc37..05c4e081a8d2 100644
--- a/drivers/misc/tps6594-pfsm.c
+++ b/drivers/misc/tps6594-pfsm.c
@@ -281,6 +281,11 @@ static int tps6594_pfsm_probe(struct platform_device *pdev)
 	pfsm->miscdev.minor = MISC_DYNAMIC_MINOR;
 	pfsm->miscdev.name = devm_kasprintf(dev, GFP_KERNEL, "pfsm-%ld-0x%02x",
 					    tps->chip_id, tps->reg);
+	if (!pfsm->miscdev.name) {
+		devm_kfree(dev, pfsm);
+		return -ENOMEM;
+	}
+
 	pfsm->miscdev.fops = &tps6594_pfsm_fops;
 	pfsm->miscdev.parent = dev->parent;
 	pfsm->chip_id = tps->chip_id;
-- 
2.43.0

On Thu, Apr 10, 2025 at 06:52:53PM +0800, Charles Han wrote:
> devm_kasprintf() can return a NULL pointer on failure,but this
> returned value in tps6594_pfsm_probe() is not checked.
> Add NULL check in tps6594_pfsm_probe(), to handle kernel NULL
> pointer dereference error.
> 
> Fixes: a0df3ef087f8 ("misc: tps6594-pfsm: Add driver for TI TPS6594 PFSM")
> Signed-off-by: Charles Han <hanchunchao@inspur.com>
> ---
>  drivers/misc/tps6594-pfsm.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/misc/tps6594-pfsm.c b/drivers/misc/tps6594-pfsm.c
> index 0a24ce44cc37..05c4e081a8d2 100644
> --- a/drivers/misc/tps6594-pfsm.c
> +++ b/drivers/misc/tps6594-pfsm.c
> @@ -281,6 +281,11 @@ static int tps6594_pfsm_probe(struct platform_device *pdev)
>  	pfsm->miscdev.minor = MISC_DYNAMIC_MINOR;
>  	pfsm->miscdev.name = devm_kasprintf(dev, GFP_KERNEL, "pfsm-%ld-0x%02x",
>  					    tps->chip_id, tps->reg);
> +	if (!pfsm->miscdev.name) {
> +		devm_kfree(dev, pfsm);
> +		return -ENOMEM;
> +	}

How was this found and tested?

thanks,

greg k-h

On Thu, Apr 10, 2025 at 06:52:53PM +0800, Charles Han wrote:
> devm_kasprintf() can return a NULL pointer on failure,but this
> returned value in tps6594_pfsm_probe() is not checked.
> Add NULL check in tps6594_pfsm_probe(), to handle kernel NULL
> pointer dereference error.
> 
> Fixes: a0df3ef087f8 ("misc: tps6594-pfsm: Add driver for TI TPS6594 PFSM")
> Signed-off-by: Charles Han <hanchunchao@inspur.com>
> ---
>  drivers/misc/tps6594-pfsm.c | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/drivers/misc/tps6594-pfsm.c b/drivers/misc/tps6594-pfsm.c
> index 0a24ce44cc37..05c4e081a8d2 100644
> --- a/drivers/misc/tps6594-pfsm.c
> +++ b/drivers/misc/tps6594-pfsm.c
> @@ -281,6 +281,11 @@ static int tps6594_pfsm_probe(struct platform_device *pdev)
>  	pfsm->miscdev.minor = MISC_DYNAMIC_MINOR;
>  	pfsm->miscdev.name = devm_kasprintf(dev, GFP_KERNEL, "pfsm-%ld-0x%02x",
>  					    tps->chip_id, tps->reg);
> +	if (!pfsm->miscdev.name) {
> +		devm_kfree(dev, pfsm);
> +		return -ENOMEM;
> +	}
> +
>  	pfsm->miscdev.fops = &tps6594_pfsm_fops;
>  	pfsm->miscdev.parent = dev->parent;
>  	pfsm->chip_id = tps->chip_id;
> -- 
> 2.43.0
> 

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

On Thu, Apr 10, 2025, at 12:52, Charles Han wrote:
> +	if (!pfsm->miscdev.name) {
> +		devm_kfree(dev, pfsm);
> +		return -ENOMEM;
> +	}

Since this is the probe function, you don't need to call devm_kfree()
but just let devres take care of it.

     Arnd