[PATCH v2] wifi: rtw89: debug: Fix memory leak in __print_txpwr_map()

[Zilin Guan]

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.

Since the validation of max_valid_addr does not depend on the allocated
memory, fix this by moving the vzalloc() call after the check.

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")
Suggested-by: Zong-Zhe Yang <kevin_yang@xxxxxxxxxxx>
Signed-off-by: Zilin Guan <zilin@xxxxxxxxxx>
---
Changes in v2:
- Move memory allocation after validation check to avoid leak.

 drivers/net/wireless/realtek/rtw89/debug.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/realtek/rtw89/debug.c b/drivers/net/wireless/realtek/rtw89/debug.c
index 1264c2f82600..987eef8170f2 100644
--- a/drivers/net/wireless/realtek/rtw89/debug.c
+++ b/drivers/net/wireless/realtek/rtw89/debug.c
@@ -825,10 +825,6 @@ static ssize_t __print_txpwr_map(struct rtw89_dev *rtwdev, char *buf, size_t buf
 	s8 *bufp, tmp;
 	int ret;
 
-	bufp = vzalloc(map->addr_to - map->addr_from + 4);
-	if (!bufp)
-		return -ENOMEM;
-
 	if (path_num == 1)
 		max_valid_addr = map->addr_to_1ss;
 	else
@@ -837,6 +833,10 @@ static ssize_t __print_txpwr_map(struct rtw89_dev *rtwdev, char *buf, size_t buf
 	if (max_valid_addr == 0)
 		return -EOPNOTSUPP;
 
+	bufp = vzalloc(map->addr_to - map->addr_from + 4);
+	if (!bufp)
+		return -ENOMEM;
+
 	for (addr = map->addr_from; addr <= max_valid_addr; addr += 4) {
 		ret = rtw89_mac_txpwr_read32(rtwdev, RTW89_PHY_0, addr, &val);
 		if (ret)
-- 
2.34.1