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 612A812BF1C; Tue, 23 Jan 2024 00:14:59 +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=1705968899; cv=none; b=u9K2dnmUWJetfzE23YohWSHGdc+oa0XFsJx6SKPKFBTk6b46ZRLE0ql+Yw0Skd9Q85LjvSdLasD+Rp7Bgm+LFycP5RW9kGhyMkERinmKYy8jMthOLctmtbbmOPVywU8gR4xMzQs7OJpPAvjL4TTnl7OCAmVTrZAI/la7mgOk62o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705968899; c=relaxed/simple; bh=skM6pdCDlfPLAzh+VJsoPkpR3yEXWlJYIzlvI3TJ+L4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=J+iwx2yMMANr41tZc/rSbLJ3awuvTralodn31gxmLjH2VE8o5KsdVDc2cFcN03V+cX7UwSHfGTIB6VO3m4T6NOMO8B+hP/+ZZSlyDgMdQCfZv6IWOtPrXEbMZ5GP7zXOfmDW4l2PWVyN6APfoaJR9nA4kekFEb3u5URdAqzsuTU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=sJz5v7QH; 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="sJz5v7QH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1FC86C4167D; Tue, 23 Jan 2024 00:14:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1705968899; bh=skM6pdCDlfPLAzh+VJsoPkpR3yEXWlJYIzlvI3TJ+L4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sJz5v7QHnzFKhdYboZTbklgxdC2KUf2cHXt7267J645ulO70RXBTy3fRdNrg6U2jG o+hffb5/URFcnylCDbnV+esup2wchrYwhbFACgbCxohz79qCkKhpzj91xVri5nPdQP b0u1nSMBHNFlVO7laPnUdI4FCRCVjlccuv0Qg+qg= 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 5.4 088/194] wifi: rtlwifi: rtl8821ae: phy: fix an undefined bitwise shift behavior Date: Mon, 22 Jan 2024 15:56:58 -0800 Message-ID: <20240122235723.019123987@linuxfoundation.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20240122235719.206965081@linuxfoundation.org> References: <20240122235719.206965081@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.4-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 11f31d006280..6a5d9d1b2947 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