Received-SPF: pass (google.com: domain of linux-wireless-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Arnd Bergmann <arnd@kernel.org>
To:     Ping-Ke Shih <pkshih@realtek.com>, Kalle Valo <kvalo@kernel.org>
Cc:     Arnd Bergmann <arnd@arndb.de>, Ching-Te Ku <ku920601@realtek.com>,
        linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] rtw89: use flexible array member in rtw89_btc_btf_tlv
Date:   Tue, 23 May 2023 13:32:35 +0200
Message-Id: <20230523113241.2772811-1-arnd@kernel.org>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: Arnd Bergmann <arnd@arndb.de>

struct rtw89_btc_btf_tlv contains a one-byte member that is intended as a
flexible array:

In function 'fortify_memcpy_chk',
    inlined from '_append_tdma' at drivers/net/wireless/realtek/rtw89/coex.c:1579:3:
include/linux/fortify-string.h:583:25: error: call to '__write_overflow_field' declared with attribute warning: detected write beyond size of field (1st parameter); maybe use struct_group()? [-Werror=attribute-warning]
  583 |                         __write_overflow_field(p_size_field, size);
      |                         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Make this actually use a flexible array to let the compiler understand.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/net/wireless/realtek/rtw89/coex.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/wireless/realtek/rtw89/coex.c b/drivers/net/wireless/realtek/rtw89/coex.c
index 3a586a971e8f..bda0e1e99a8c 100644
--- a/drivers/net/wireless/realtek/rtw89/coex.c
+++ b/drivers/net/wireless/realtek/rtw89/coex.c
@@ -206,7 +206,7 @@ static const struct rtw89_btc_ver rtw89_btc_ver_defs[] = {
 struct rtw89_btc_btf_tlv {
 	u8 type;
 	u8 len;
-	u8 val[1];
+	u8 val[];
 } __packed;
 
 enum btc_btf_set_report_en {
-- 
2.39.2