[PATCH] rtw89: avoid stringop-overflow warning

[PATCH] rtw89: avoid stringop-overflow warning

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

After -Wstringop-overflow got enabled, the rtw89 driver produced
two odd warnings with gcc-13:

drivers/net/wireless/realtek/rtw89/coex.c: In function 'rtw89_btc_ntfy_scan_start':
drivers/net/wireless/realtek/rtw89/coex.c:5362:50: error: writing 1 byte into a region of size 0 [-Werror=stringop-overflow=]
 5362 |                 wl->dbcc_info.scan_band[phy_idx] = band;
      |                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~
In file included from drivers/net/wireless/realtek/rtw89/coex.h:8,
                 from drivers/net/wireless/realtek/rtw89/coex.c:5:
drivers/net/wireless/realtek/rtw89/core.h:1441:12: note: at offset [64, 255] into destination object 'scan_band' of size 2
 1441 |         u8 scan_band[RTW89_PHY_MAX]; /* scan band in  each phy */
      |            ^~~~~~~~~
drivers/net/wireless/realtek/rtw89/coex.c: In function 'rtw89_btc_ntfy_switch_band':
drivers/net/wireless/realtek/rtw89/coex.c:5406:50: error: writing 1 byte into a region of size 0 [-Werror=stringop-overflow=]
 5406 |                 wl->dbcc_info.scan_band[phy_idx] = band;
      |                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~
drivers/net/wireless/realtek/rtw89/core.h:1441:12: note: at offset [64, 255] into destination object 'scan_band' of size 2
 1441 |         u8 scan_band[RTW89_PHY_MAX]; /* scan band in  each phy */
      |            ^~~~~~~~~

I don't know what happened here, but adding an explicit range check
shuts up the output.

Fixes: 89741e7e42f6 ("Makefile: Enable -Wstringop-overflow globally")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/net/wireless/realtek/rtw89/coex.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/net/wireless/realtek/rtw89/coex.c b/drivers/net/wireless/realtek/rtw89/coex.c
index b842cd9a86f8..9c0db35d3e13 100644
--- a/drivers/net/wireless/realtek/rtw89/coex.c
+++ b/drivers/net/wireless/realtek/rtw89/coex.c
@@ -5352,6 +5352,10 @@ void rtw89_btc_ntfy_scan_start(struct rtw89_dev *rtwdev, u8 phy_idx, u8 band)
 	rtw89_debug(rtwdev, RTW89_DBG_BTC,
 		    "[BTC], %s(): phy_idx=%d, band=%d\n",
 		    __func__, phy_idx, band);
+
+	if (phy_idx >= RTW89_PHY_MAX)
+		return;
+
 	btc->dm.cnt_notify[BTC_NCNT_SCAN_START]++;
 	wl->status.map.scan = true;
 	wl->scan_info.band[phy_idx] = band;
@@ -5396,6 +5400,10 @@ void rtw89_btc_ntfy_switch_band(struct rtw89_dev *rtwdev, u8 phy_idx, u8 band)
 	rtw89_debug(rtwdev, RTW89_DBG_BTC,
 		    "[BTC], %s(): phy_idx=%d, band=%d\n",
 		    __func__, phy_idx, band);
+
+	if (phy_idx >= RTW89_PHY_MAX)
+		return;
+
 	btc->dm.cnt_notify[BTC_NCNT_SWITCH_BAND]++;
 
 	wl->scan_info.band[phy_idx] = band;
-- 
2.39.2

RE: [PATCH] rtw89: avoid stringop-overflow warning

[Ping-Ke Shih]

> -----Original Message-----
> From: Arnd Bergmann <arnd@kernel.org>
> Sent: Monday, December 4, 2023 3:30 PM
> To: Ping-Ke Shih <pkshih@realtek.com>; Kalle Valo <kvalo@kernel.org>; Gustavo A. R. Silva
> <gustavoars@kernel.org>
> Cc: Arnd Bergmann <arnd@arndb.de>; DeanKu <ku920601@realtek.com>; linux-wireless@vger.kernel.org;
> linux-kernel@vger.kernel.org
> Subject: [PATCH] rtw89: avoid stringop-overflow warning

Subject prefix should be "wifi: rtw89: ..."

> 
> From: Arnd Bergmann <arnd@arndb.de>
> 
> After -Wstringop-overflow got enabled, the rtw89 driver produced
> two odd warnings with gcc-13:
> 
> drivers/net/wireless/realtek/rtw89/coex.c: In function 'rtw89_btc_ntfy_scan_start':
> drivers/net/wireless/realtek/rtw89/coex.c:5362:50: error: writing 1 byte into a region of size 0
> [-Werror=stringop-overflow=]
>  5362 |                 wl->dbcc_info.scan_band[phy_idx] = band;
>       |                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~
> In file included from drivers/net/wireless/realtek/rtw89/coex.h:8,
>                  from drivers/net/wireless/realtek/rtw89/coex.c:5:
> drivers/net/wireless/realtek/rtw89/core.h:1441:12: note: at offset [64, 255] into destination object
> 'scan_band' of size 2
>  1441 |         u8 scan_band[RTW89_PHY_MAX]; /* scan band in  each phy */
>       |            ^~~~~~~~~
> drivers/net/wireless/realtek/rtw89/coex.c: In function 'rtw89_btc_ntfy_switch_band':
> drivers/net/wireless/realtek/rtw89/coex.c:5406:50: error: writing 1 byte into a region of size 0
> [-Werror=stringop-overflow=]
>  5406 |                 wl->dbcc_info.scan_band[phy_idx] = band;
>       |                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~
> drivers/net/wireless/realtek/rtw89/core.h:1441:12: note: at offset [64, 255] into destination object
> 'scan_band' of size 2
>  1441 |         u8 scan_band[RTW89_PHY_MAX]; /* scan band in  each phy */
>       |            ^~~~~~~~~
> 
> I don't know what happened here, but adding an explicit range check
> shuts up the output.

The callers of these two cases will pass RTW89_PHY_0 (0) as argument of phy_idx,
and will extend to pass RTW89_PHY_1 (1) in the future, but should not be larger
than 1.

I don't mind to add this checking, but I really don't know what happened neither.
A statement 'wl->scan_info.band[phy_idx] = band;' did similar thing in the same
function, but why doesn't gcc complain this?

Re: [PATCH] rtw89: avoid stringop-overflow warning

[Kalle Valo]

Arnd Bergmann <arnd@kernel.org> wrote:

> From: Arnd Bergmann <arnd@arndb.de>
> 
> After -Wstringop-overflow got enabled, the rtw89 driver produced
> two odd warnings with gcc-13:
> 
> drivers/net/wireless/realtek/rtw89/coex.c: In function 'rtw89_btc_ntfy_scan_start':
> drivers/net/wireless/realtek/rtw89/coex.c:5362:50: error: writing 1 byte into a region of size 0 [-Werror=stringop-overflow=]
>  5362 |                 wl->dbcc_info.scan_band[phy_idx] = band;
>       |                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~
> In file included from drivers/net/wireless/realtek/rtw89/coex.h:8,
>                  from drivers/net/wireless/realtek/rtw89/coex.c:5:
> drivers/net/wireless/realtek/rtw89/core.h:1441:12: note: at offset [64, 255] into destination object 'scan_band' of size 2
>  1441 |         u8 scan_band[RTW89_PHY_MAX]; /* scan band in  each phy */
>       |            ^~~~~~~~~
> drivers/net/wireless/realtek/rtw89/coex.c: In function 'rtw89_btc_ntfy_switch_band':
> drivers/net/wireless/realtek/rtw89/coex.c:5406:50: error: writing 1 byte into a region of size 0 [-Werror=stringop-overflow=]
>  5406 |                 wl->dbcc_info.scan_band[phy_idx] = band;
>       |                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~
> drivers/net/wireless/realtek/rtw89/core.h:1441:12: note: at offset [64, 255] into destination object 'scan_band' of size 2
>  1441 |         u8 scan_band[RTW89_PHY_MAX]; /* scan band in  each phy */
>       |            ^~~~~~~~~
> 
> I don't know what happened here, but adding an explicit range check
> shuts up the output.
> 
> Fixes: 89741e7e42f6 ("Makefile: Enable -Wstringop-overflow globally")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

ERROR: 'wifi:' prefix missing: '[PATCH] rtw89: avoid stringop-overflow warning'
ERROR: Failed to find commit id: Fixes: 89741e7e42f6 ("Makefile: Enable -Wstringop-overflow globally")

I can add the "wifi:" prefix but where can I find the commit 89741e7e42f6?

-- 
https://patchwork.kernel.org/project/linux-wireless/patch/20231204073020.1105416-1-arnd@kernel.org/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches

Re: [PATCH] rtw89: avoid stringop-overflow warning

[Arnd Bergmann]

On Thu, Dec 7, 2023, at 16:47, Kalle Valo wrote:
> Arnd Bergmann <arnd@kernel.org> wrote:
>> From: Arnd Bergmann <arnd@arndb.de>
>> 
>> Fixes: 89741e7e42f6 ("Makefile: Enable -Wstringop-overflow globally")
>> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
>
> ERROR: 'wifi:' prefix missing: '[PATCH] rtw89: avoid stringop-overflow 
> warning'
> ERROR: Failed to find commit id: Fixes: 89741e7e42f6 ("Makefile: Enable 
> -Wstringop-overflow globally")
>
> I can add the "wifi:" prefix but where can I find the commit 89741e7e42f6?

It's in linux-next and came in from Gustavo's tree at
https://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux.git/log/?h=for-next/kspp

    Arnd

Re: [PATCH] rtw89: avoid stringop-overflow warning

[Kalle Valo]

"Arnd Bergmann" <arnd@arndb.de> writes:

> On Thu, Dec 7, 2023, at 16:47, Kalle Valo wrote:
>> Arnd Bergmann <arnd@kernel.org> wrote:
>>> From: Arnd Bergmann <arnd@arndb.de>
>>> 
>>> Fixes: 89741e7e42f6 ("Makefile: Enable -Wstringop-overflow globally")
>>> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
>>
>> ERROR: 'wifi:' prefix missing: '[PATCH] rtw89: avoid stringop-overflow 
>> warning'
>> ERROR: Failed to find commit id: Fixes: 89741e7e42f6 ("Makefile: Enable 
>> -Wstringop-overflow globally")
>>
>> I can add the "wifi:" prefix but where can I find the commit 89741e7e42f6?
>
> It's in linux-next and came in from Gustavo's tree at
> https://git.kernel.org/pub/scm/linux/kernel/git/gustavoars/linux.git/log/?h=for-next/kspp

Ah, I think then I'll drop the Fixes tag to avoid warnings or reports.
My understanding is that a commit in the Fixes tag should be a parent.

-- 
https://patchwork.kernel.org/project/linux-wireless/list/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches

Re: wifi: rtw89: avoid stringop-overflow warning

[Kalle Valo]

Arnd Bergmann <arnd@kernel.org> wrote:

> From: Arnd Bergmann <arnd@arndb.de>
> 
> After -Wstringop-overflow got enabled, the rtw89 driver produced
> two odd warnings with gcc-13:
> 
> drivers/net/wireless/realtek/rtw89/coex.c: In function 'rtw89_btc_ntfy_scan_start':
> drivers/net/wireless/realtek/rtw89/coex.c:5362:50: error: writing 1 byte into a region of size 0 [-Werror=stringop-overflow=]
>  5362 |                 wl->dbcc_info.scan_band[phy_idx] = band;
>       |                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~
> In file included from drivers/net/wireless/realtek/rtw89/coex.h:8,
>                  from drivers/net/wireless/realtek/rtw89/coex.c:5:
> drivers/net/wireless/realtek/rtw89/core.h:1441:12: note: at offset [64, 255] into destination object 'scan_band' of size 2
>  1441 |         u8 scan_band[RTW89_PHY_MAX]; /* scan band in  each phy */
>       |            ^~~~~~~~~
> drivers/net/wireless/realtek/rtw89/coex.c: In function 'rtw89_btc_ntfy_switch_band':
> drivers/net/wireless/realtek/rtw89/coex.c:5406:50: error: writing 1 byte into a region of size 0 [-Werror=stringop-overflow=]
>  5406 |                 wl->dbcc_info.scan_band[phy_idx] = band;
>       |                 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~
> drivers/net/wireless/realtek/rtw89/core.h:1441:12: note: at offset [64, 255] into destination object 'scan_band' of size 2
>  1441 |         u8 scan_band[RTW89_PHY_MAX]; /* scan band in  each phy */
>       |            ^~~~~~~~~
> 
> I don't know what happened here, but adding an explicit range check
> shuts up the output.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Patch applied to wireless-next.git, thanks.

595b1280e2c9 wifi: rtw89: avoid stringop-overflow warning

-- 
https://patchwork.kernel.org/project/linux-wireless/patch/20231204073020.1105416-1-arnd@kernel.org/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches