[PATCH] soc: mediatek: SVS: Fix memory leak in svs_enable_debug_write()

[PATCH] soc: mediatek: SVS: Fix memory leak in svs_enable_debug_write()

[Zilin Guan]

In svs_enable_debug_write(), the buf is allocated via memdup_user_nul().
If kstrtoint() fails, the function returns directly without freeing the
allocated memory, leading to a memory leak.

Fix this by freeing buf before returning the error code.

Fixes: 13f1bbcfb582 ("soc: mediatek: SVS: add debug commands")
Co-developed-by: Jianhao Xu <jianhao.xu@seu.edu.cn>
Signed-off-by: Jianhao Xu <jianhao.xu@seu.edu.cn>
Signed-off-by: Zilin Guan <zilin@seu.edu.cn>
---
 drivers/soc/mediatek/mtk-svs.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/soc/mediatek/mtk-svs.c b/drivers/soc/mediatek/mtk-svs.c
index f45537546553..691e7e6be654 100644
--- a/drivers/soc/mediatek/mtk-svs.c
+++ b/drivers/soc/mediatek/mtk-svs.c
@@ -799,8 +799,10 @@ static ssize_t svs_enable_debug_write(struct file *filp,
 		return PTR_ERR(buf);
 
 	ret = kstrtoint(buf, 10, &enabled);
-	if (ret)
+	if (ret) {
+		kfree(buf);
 		return ret;
+	}
 
 	if (!enabled) {
 		svs_bank_disable_and_restore_default_volts(svsp, svsb);
-- 
2.34.1

Re: [PATCH] soc: mediatek: SVS: Fix memory leak in svs_enable_debug_write()

[Markus Elfring]

…
> Fix this by freeing buf before returning the error code.

How do you think about to use the attribute “__free(kfree)”?
https://elixir.bootlin.com/linux/v6.19-rc2/source/include/linux/slab.h#L512
https://elixir.bootlin.com/linux/v6.19-rc2/source/drivers/soc/mediatek/mtk-svs.c#L785-L813

Regards,
Markus

Re: [PATCH] soc: mediatek: SVS: Fix memory leak in svs_enable_debug_write()

[Zilin Guan]

On Sun, Dec 28, 2025 at 03:19:00PM+0100, Markus Elfring wrote:
> …
> > Fix this by freeing buf before returning the error code.
> 
> How do you think about to use the attribute “__free(kfree)”?
> https://elixir.bootlin.com/linux/v6.19-rc2/source/include/linux/slab.h#L512
> https://elixir.bootlin.com/linux/v6.19-rc2/source/drivers/soc/mediatek/mtk-svs.c#L785-L813
> 
> Regards,
> Markus

Hi Markus,

Thanks for the suggestion.

I agree that using the "__free(kfree)" attribute is a good way to 
simplify memory management here. I will apply this change in the 
v2 patch.

Regards,
Zilin Guan