From: Ping-Ke Shih <pkshih@realtek.com>
To: Arnd Bergmann <arnd@kernel.org>, 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-wireless@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH] rtw89: avoid stringop-overflow warning
Date: Tue, 5 Dec 2023 00:26:14 +0000 [thread overview]
Message-ID: <6161bfc56d51413283915031e8d4d653@realtek.com> (raw)
In-Reply-To: <20231204073020.1105416-1-arnd@kernel.org>
> -----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?
next prev parent reply other threads:[~2023-12-05 0:26 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-04 7:30 [PATCH] rtw89: avoid stringop-overflow warning Arnd Bergmann
2023-12-05 0:26 ` Ping-Ke Shih [this message]
2023-12-07 15:47 ` Kalle Valo
2023-12-07 16:11 ` Arnd Bergmann
2023-12-12 14:23 ` Kalle Valo
2023-12-12 15:11 ` wifi: " Kalle Valo
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