RE: [PATCH] wifi: rtw89: debug: Fix memory leak in __print_txpwr_map()

[Zong-Zhe Yang <kevin_yang@realtek.com>]

Zilin Guan <zilin@seu.edu.cn> wrote:
> 
> In __print_txpwr_map(), memory is allocated to bufp via vzalloc().
> If max_valid_addr is 0, the function returns -EOPNOTSUPP immediately
> without freeing bufp, leading to a memory leak.
> 
> Fix this by freeing the temporary buffer bufp in the error path.
> 
> Compile tested only. Issue found using a prototype static analysis tool
> and code review.
> 
> Fixes: 036042e15770 ("wifi: rtw89: debug: txpwr table supports Wi-Fi 7 chips")
> Signed-off-by: Zilin Guan <zilin@seu.edu.cn>
> ---
>  drivers/net/wireless/realtek/rtw89/debug.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/net/wireless/realtek/rtw89/debug.c
> b/drivers/net/wireless/realtek/rtw89/debug.c
> index 1264c2f82600..c7bd1d0212b6 100644
> --- a/drivers/net/wireless/realtek/rtw89/debug.c
> +++ b/drivers/net/wireless/realtek/rtw89/debug.c
> @@ -834,8 +834,10 @@ static ssize_t __print_txpwr_map(struct rtw89_dev *rtwdev, char
> *buf, size_t buf
>         else
>                 max_valid_addr = map->addr_to;
> 
> -       if (max_valid_addr == 0)
> +       if (max_valid_addr == 0) {
> +               vfree(bufp);
>                 return -EOPNOTSUPP;
> +       }

Thank you for catching this.
Since the decision for max_valid_addr doesn't depend on bufp,
how about moving vzalloc down here ?

> 
>         for (addr = map->addr_from; addr <= max_valid_addr; addr += 4) {
>                 ret = rtw89_mac_txpwr_read32(rtwdev, RTW89_PHY_0, addr, &val);
> --
> 2.34.1
>