[PATCH] ipmi: Use devm_kasprintf

[PATCH] ipmi: Use devm_kasprintf

[zhangjiao2]

From: zhang jiao <zhangjiao2@cmss.chinamobile.com>

Use devm_kasprintf to simplify code.

Signed-off-by: zhang jiao <zhangjiao2@cmss.chinamobile.com>
---
 drivers/char/ipmi/ipmi_msghandler.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
index e12b531f5c2f..5d78b1fe49a8 100644
--- a/drivers/char/ipmi/ipmi_msghandler.c
+++ b/drivers/char/ipmi/ipmi_msghandler.c
@@ -3213,7 +3213,7 @@ static int __ipmi_bmc_register(struct ipmi_smi *intf,
 
 	if (intf_num == -1)
 		intf_num = intf->intf_num;
-	intf->my_dev_name = kasprintf(GFP_KERNEL, "ipmi%d", intf_num);
+	intf->my_dev_name = devm_kasprintf(intf->si_dev, GFP_KERNEL, "ipmi%d", intf_num);
 	if (!intf->my_dev_name) {
 		rv = -ENOMEM;
 		dev_err(intf->si_dev, "Unable to allocate link from BMC: %d\n",
@@ -3226,7 +3226,7 @@ static int __ipmi_bmc_register(struct ipmi_smi *intf,
 	if (rv) {
 		dev_err(intf->si_dev, "Unable to create symlink to bmc: %d\n",
 			rv);
-		goto out_free_my_dev_name;
+		goto out_unlink1;
 	}
 
 	intf->bmc_registered = true;
@@ -3237,11 +3237,6 @@ static int __ipmi_bmc_register(struct ipmi_smi *intf,
 	intf->in_bmc_register = false;
 	return rv;
 
-
-out_free_my_dev_name:
-	kfree(intf->my_dev_name);
-	intf->my_dev_name = NULL;
-
 out_unlink1:
 	sysfs_remove_link(&intf->si_dev->kobj, "bmc");
 
-- 
2.33.0

Re: [PATCH] ipmi: Use devm_kasprintf

[Christophe JAILLET]

Le 04/09/2024 à 06:12, zhangjiao2 a écrit :
> From: zhang jiao <zhangjiao2@cmss.chinamobile.com>
> 
> Use devm_kasprintf to simplify code.

Hi,

I don't think that it is correct because __ipmi_bmc_register() is not a 
probe function ans is not called from a probe function. So it is really 
unlikely that a devm_ function is correct.

The kasprintf() you are removing is balanced by a kfree() in 
__ipmi_bmc_unregister().
So you patch would lead to a potential double-free issue.

CJ

> 
> Signed-off-by: zhang jiao <zhangjiao2@cmss.chinamobile.com>
> ---
>   drivers/char/ipmi/ipmi_msghandler.c | 9 ++-------
>   1 file changed, 2 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
> index e12b531f5c2f..5d78b1fe49a8 100644
> --- a/drivers/char/ipmi/ipmi_msghandler.c
> +++ b/drivers/char/ipmi/ipmi_msghandler.c
> @@ -3213,7 +3213,7 @@ static int __ipmi_bmc_register(struct ipmi_smi *intf,
>   
>   	if (intf_num == -1)
>   		intf_num = intf->intf_num;
> -	intf->my_dev_name = kasprintf(GFP_KERNEL, "ipmi%d", intf_num);
> +	intf->my_dev_name = devm_kasprintf(intf->si_dev, GFP_KERNEL, "ipmi%d", intf_num);
>   	if (!intf->my_dev_name) {
>   		rv = -ENOMEM;
>   		dev_err(intf->si_dev, "Unable to allocate link from BMC: %d\n",
> @@ -3226,7 +3226,7 @@ static int __ipmi_bmc_register(struct ipmi_smi *intf,
>   	if (rv) {
>   		dev_err(intf->si_dev, "Unable to create symlink to bmc: %d\n",
>   			rv);
> -		goto out_free_my_dev_name;
> +		goto out_unlink1;
>   	}
>   
>   	intf->bmc_registered = true;
> @@ -3237,11 +3237,6 @@ static int __ipmi_bmc_register(struct ipmi_smi *intf,
>   	intf->in_bmc_register = false;
>   	return rv;
>   
> -
> -out_free_my_dev_name:
> -	kfree(intf->my_dev_name);
> -	intf->my_dev_name = NULL;
> -
>   out_unlink1:
>   	sysfs_remove_link(&intf->si_dev->kobj, "bmc");
>   

Re: [Openipmi-developer] [PATCH] ipmi: Use devm_kasprintf

[Corey Minyard]

On Wed, Sep 04, 2024 at 07:41:32PM +0200, Christophe JAILLET via Openipmi-developer wrote:
> Le 04/09/2024 à 06:12, zhangjiao2 a écrit :
> > From: zhang jiao <zhangjiao2@cmss.chinamobile.com>
> > 
> > Use devm_kasprintf to simplify code.
> 
> Hi,
> 
> I don't think that it is correct because __ipmi_bmc_register() is not a
> probe function ans is not called from a probe function. So it is really
> unlikely that a devm_ function is correct.
> 
> The kasprintf() you are removing is balanced by a kfree() in
> __ipmi_bmc_unregister().
> So you patch would lead to a potential double-free issue.

Yes, this is incorrect from a number of points of view.

-corey

> 
> CJ
> 
> > 
> > Signed-off-by: zhang jiao <zhangjiao2@cmss.chinamobile.com>
> > ---
> >   drivers/char/ipmi/ipmi_msghandler.c | 9 ++-------
> >   1 file changed, 2 insertions(+), 7 deletions(-)
> > 
> > diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
> > index e12b531f5c2f..5d78b1fe49a8 100644
> > --- a/drivers/char/ipmi/ipmi_msghandler.c
> > +++ b/drivers/char/ipmi/ipmi_msghandler.c
> > @@ -3213,7 +3213,7 @@ static int __ipmi_bmc_register(struct ipmi_smi *intf,
> >   	if (intf_num == -1)
> >   		intf_num = intf->intf_num;
> > -	intf->my_dev_name = kasprintf(GFP_KERNEL, "ipmi%d", intf_num);
> > +	intf->my_dev_name = devm_kasprintf(intf->si_dev, GFP_KERNEL, "ipmi%d", intf_num);
> >   	if (!intf->my_dev_name) {
> >   		rv = -ENOMEM;
> >   		dev_err(intf->si_dev, "Unable to allocate link from BMC: %d\n",
> > @@ -3226,7 +3226,7 @@ static int __ipmi_bmc_register(struct ipmi_smi *intf,
> >   	if (rv) {
> >   		dev_err(intf->si_dev, "Unable to create symlink to bmc: %d\n",
> >   			rv);
> > -		goto out_free_my_dev_name;
> > +		goto out_unlink1;
> >   	}
> >   	intf->bmc_registered = true;
> > @@ -3237,11 +3237,6 @@ static int __ipmi_bmc_register(struct ipmi_smi *intf,
> >   	intf->in_bmc_register = false;
> >   	return rv;
> > -
> > -out_free_my_dev_name:
> > -	kfree(intf->my_dev_name);
> > -	intf->my_dev_name = NULL;
> > -
> >   out_unlink1:
> >   	sysfs_remove_link(&intf->si_dev->kobj, "bmc");
> 
> 
> 
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