From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6F9A655C34; Tue, 23 Jan 2024 01:40:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705974015; cv=none; b=FhrGq3yNraMl1E311RMfLzD4ewYdAt0EX6hvFFYIiNE1QnyxDIpp8AHZAcJozENQfchYblp3wcUJLdBRYOhDn2LCLussmwtsZmz8AOMlCfIhzrOJJeadIzWsie4jbWy9TgBVG/+K8IW7HAzEzJfyN27W6RQFd32c4vxuzK2eEuI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705974015; c=relaxed/simple; bh=0evuUFbXAMh1ItDyCk3/GI9Nu0DkgG7kThtcZoWXWaQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=WqzFZvel61jEO1rS21oQeM+WXvdCLJwK5hCy8ufDWfQd1b4Je0lXc8GCdnSvROewCiPSQ60757vhnT3duGPJ26Knl1Rym93mSYAnwYbliAeszkHBi7K3Q5ofdW/6kR+OSjOaMFunvMZ71UKtYrzBRuhkkBrX+KyX25vheOyuOdE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=f9CpZFLN; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="f9CpZFLN" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 70381C433A6; Tue, 23 Jan 2024 01:40:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1705974014; bh=0evuUFbXAMh1ItDyCk3/GI9Nu0DkgG7kThtcZoWXWaQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=f9CpZFLNjAATBfa8Cv16QnqutiCPm6wRDO9jHo7fOW16NMRId/F2EkOxD+sgsllNO VoOcDxZdRVC3s6PPo/S90Qlzsr4PH1Jh3bzjGleGdvvFJMWZgL0GyDYTVBH89RJjqi tY458dhPibWUeaMqpS86qKeOV18tPChhv0s1Y7Ew= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Su Hui , Ping-Ke Shih , Kalle Valo , Sasha Levin Subject: [PATCH 5.15 126/374] wifi: rtlwifi: rtl8821ae: phy: fix an undefined bitwise shift behavior Date: Mon, 22 Jan 2024 15:56:22 -0800 Message-ID: <20240122235749.025386446@linuxfoundation.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240122235744.598274724@linuxfoundation.org> References: <20240122235744.598274724@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.15-stable review patch. If anyone has any objections, please let me know. ------------------ From: Su Hui [ Upstream commit bc8263083af60e7e57c6120edbc1f75d6c909a35 ] Clang static checker warns: drivers/net/wireless/realtek/rtlwifi/rtl8821ae/phy.c:184:49: The result of the left shift is undefined due to shifting by '32', which is greater or equal to the width of type 'u32'. [core.UndefinedBinaryOperatorResult] If the value of the right operand is negative or is greater than or equal to the width of the promoted left operand, the behavior is undefined.[1][2] For example, when using different gcc's compilation optimization options (-O0 or -O2), the result of '(u32)data << 32' is different. One is 0, the other is old value of data. Let _rtl8821ae_phy_calculate_bit_shift()'s return value less than 32 to fix this problem. Warn if bitmask is zero. [1] https://stackoverflow.com/questions/11270492/what-does-the-c-standard-say-about-bitshifting-more-bits-than-the-width-of-type [2] https://www.open-std.org/jtc1/sc22/wg14/www/docs/n1256.pdf Fixes: 21e4b0726dc6 ("rtlwifi: rtl8821ae: Move driver from staging to regular tree") Signed-off-by: Su Hui Acked-by: Ping-Ke Shih Signed-off-by: Kalle Valo Link: https://lore.kernel.org/r/20231127013511.26694-2-suhui@nfschina.com Signed-off-by: Sasha Levin --- drivers/net/wireless/realtek/rtlwifi/rtl8821ae/phy.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/drivers/net/wireless/realtek/rtlwifi/rtl8821ae/phy.c b/drivers/net/wireless/realtek/rtlwifi/rtl8821ae/phy.c index 5323ead30db0..fa1839d8ee55 100644 --- a/drivers/net/wireless/realtek/rtlwifi/rtl8821ae/phy.c +++ b/drivers/net/wireless/realtek/rtlwifi/rtl8821ae/phy.c @@ -29,9 +29,10 @@ static void _rtl8821ae_phy_rf_serial_write(struct ieee80211_hw *hw, u32 data); static u32 _rtl8821ae_phy_calculate_bit_shift(u32 bitmask) { - u32 i = ffs(bitmask); + if (WARN_ON_ONCE(!bitmask)) + return 0; - return i ? i - 1 : 32; + return __ffs(bitmask); } static bool _rtl8821ae_phy_bb8821a_config_parafile(struct ieee80211_hw *hw); /*static bool _rtl8812ae_phy_config_mac_with_headerfile(struct ieee80211_hw *hw);*/ -- 2.43.0