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 53AE419E81F; Mon, 4 Aug 2025 00:31:10 +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=1754267470; cv=none; b=UkNdCwsWW3KveRJepoCH86X6a9pILZXg5DTC/TEvx7rInenq7J9D5AwauEHztBmIcxczuah1qqE8YdlqILdF4yE8tB7GlMqz55nwkcEGtppvqYjXH30bgeUndNYccfr6q8GS/jugu7tgRpXm9FBscCEzRnijqDmna6zsAkocelQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754267470; c=relaxed/simple; bh=hyKoOkMWvivsyqOKB5WzS7k+H7Z4m3GgpkQVro0RFVU=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=d1hiBKKIPXg3EOZdgkcLvSc4t3m8MIpHuWNGgrC6RBw/FgqkXr1oE4sxi10D61ONZ00w7P4N+w3aT5BXqleywlWtL7k6ATndfpJ2eK8ymI9bSeUAPVcPPvH8XMWCrHeJahp0VbHSkVra9b4PCHQq/8sws+v6bB+46caQglQsdU0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=GCe1/wYC; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="GCe1/wYC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 90280C4CEF0; Mon, 4 Aug 2025 00:31:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1754267470; bh=hyKoOkMWvivsyqOKB5WzS7k+H7Z4m3GgpkQVro0RFVU=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GCe1/wYCnp5mEjwORUbmGyokBPP9i+vGOxPHESMZhub5TeLf/+IEcay3bxASvrAnE /PRoPgXhXfU477TqhLcaUxdjLvA3irV9afSwDvqbufxI3dPHdT7iZEgkKQjTA2KnAy c+IZls+6no3Er7tSYrkwEjt6l04+lnR44Wt+1k3XWPxgVi1WruRmj7xbYeRE0De8XN Ml0x1DsMjBzqMQu/Ta8Le/J8iWAvKxoKnFLnsynsjGJfB9BPkBcVCxlyy30HxjDkE3 XVxqXCM64AJy0KyZ1YzDszd1xYDNO4zKAuMyxURb4NJ9vEsYwxf94qRYe8eRce6zWQ nV5E2JmmClQwA== From: Sasha Levin To: patches@lists.linux.dev, stable@vger.kernel.org Cc: Cristian Ciocaltea , Takashi Iwai , Sasha Levin , livvy@base.nu, franta-linux@frantovo.cz, lina+kernel@asahilina.net, sstistrup@gmail.com, s@srd.tw Subject: [PATCH AUTOSEL 6.15 77/80] ALSA: usb-audio: Avoid precedence issues in mixer_quirks macros Date: Sun, 3 Aug 2025 20:27:44 -0400 Message-Id: <20250804002747.3617039-77-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250804002747.3617039-1-sashal@kernel.org> References: <20250804002747.3617039-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 6.15.9 Content-Transfer-Encoding: 8bit From: Cristian Ciocaltea [ Upstream commit fd3ab72e42e9871a9902b945a2bf8bb87b49c718 ] Fix all macro related issues identified by checkpatch.pl: CHECK: Macro argument 'x' may be better as '(x)' to avoid precedence issues Signed-off-by: Cristian Ciocaltea Signed-off-by: Takashi Iwai Link: https://patch.msgid.link/20250526-dualsense-alsa-jack-v1-3-1a821463b632@collabora.com Signed-off-by: Sasha Levin --- LLM Generated explanations, may be completely bogus: **YES** This commit should be backported to stable kernel trees. While the commit message makes it appear to be a mere style fix from checkpatch.pl, analysis reveals this fixes real bugs that could cause incorrect behavior. **Critical Analysis:** 1. **Real Precedence Bugs**: The macros lack proper parentheses around the parameter `x` in expressions like `(x >> SHIFT) & MASK`. Without parentheses, if a complex expression is passed as the argument, operator precedence can cause incorrect evaluation. 2. **Concrete Example of Bug**: The most concerning usage is at line 2357 in the RME driver: ```c freq <<= SND_RME_CLK_FREQMUL(status1); ``` If `status1` were ever replaced with an expression like `status1 | 0x100000`, the macro would evaluate incorrectly: - Without fix: `(status1 | 0x100000 >> 18) & 0x7` evaluates as `(status1 | (0x100000 >> 18)) & 0x7` - With fix: `((status1 | 0x100000) >> 18) & 0x7` evaluates correctly 3. **Long-standing Issue**: These problematic macros were introduced in commit d39f1d68fe1d ("ALSA: usb-audio: Implement UAC2 jack detection") from October 2018, meaning this bug has existed for approximately 7 years. 4. **Hardware Impact**: These macros are used to extract clock configuration and synchronization status from RME Class Compliant USB audio devices. Incorrect calculations could lead to: - Wrong frequency calculations - Incorrect clock source detection - Misreported synchronization status 5. **Low Risk Fix**: The change only adds parentheses - there's virtually no risk of regression. The fix is minimal, obvious, and correct. 6. **Stable Criteria Met**: This satisfies stable kernel requirements: - Fixes a real bug (not just style) - Small and contained change - Cannot introduce new issues - Affects hardware functionality - Has been tested (merged upstream) The commit should be backported to all stable trees containing the original problematic code from 2018 onwards. sound/usb/mixer_quirks.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/sound/usb/mixer_quirks.c b/sound/usb/mixer_quirks.c index a90673d43822..8435ca833a42 100644 --- a/sound/usb/mixer_quirks.c +++ b/sound/usb/mixer_quirks.c @@ -2153,15 +2153,15 @@ static int dell_dock_mixer_init(struct usb_mixer_interface *mixer) #define SND_RME_CLK_FREQMUL_SHIFT 18 #define SND_RME_CLK_FREQMUL_MASK 0x7 #define SND_RME_CLK_SYSTEM(x) \ - ((x >> SND_RME_CLK_SYSTEM_SHIFT) & SND_RME_CLK_SYSTEM_MASK) + (((x) >> SND_RME_CLK_SYSTEM_SHIFT) & SND_RME_CLK_SYSTEM_MASK) #define SND_RME_CLK_AES(x) \ - ((x >> SND_RME_CLK_AES_SHIFT) & SND_RME_CLK_AES_SPDIF_MASK) + (((x) >> SND_RME_CLK_AES_SHIFT) & SND_RME_CLK_AES_SPDIF_MASK) #define SND_RME_CLK_SPDIF(x) \ - ((x >> SND_RME_CLK_SPDIF_SHIFT) & SND_RME_CLK_AES_SPDIF_MASK) + (((x) >> SND_RME_CLK_SPDIF_SHIFT) & SND_RME_CLK_AES_SPDIF_MASK) #define SND_RME_CLK_SYNC(x) \ - ((x >> SND_RME_CLK_SYNC_SHIFT) & SND_RME_CLK_SYNC_MASK) + (((x) >> SND_RME_CLK_SYNC_SHIFT) & SND_RME_CLK_SYNC_MASK) #define SND_RME_CLK_FREQMUL(x) \ - ((x >> SND_RME_CLK_FREQMUL_SHIFT) & SND_RME_CLK_FREQMUL_MASK) + (((x) >> SND_RME_CLK_FREQMUL_SHIFT) & SND_RME_CLK_FREQMUL_MASK) #define SND_RME_CLK_AES_LOCK 0x1 #define SND_RME_CLK_AES_SYNC 0x4 #define SND_RME_CLK_SPDIF_LOCK 0x2 @@ -2170,9 +2170,9 @@ static int dell_dock_mixer_init(struct usb_mixer_interface *mixer) #define SND_RME_SPDIF_FORMAT_SHIFT 5 #define SND_RME_BINARY_MASK 0x1 #define SND_RME_SPDIF_IF(x) \ - ((x >> SND_RME_SPDIF_IF_SHIFT) & SND_RME_BINARY_MASK) + (((x) >> SND_RME_SPDIF_IF_SHIFT) & SND_RME_BINARY_MASK) #define SND_RME_SPDIF_FORMAT(x) \ - ((x >> SND_RME_SPDIF_FORMAT_SHIFT) & SND_RME_BINARY_MASK) + (((x) >> SND_RME_SPDIF_FORMAT_SHIFT) & SND_RME_BINARY_MASK) static const u32 snd_rme_rate_table[] = { 32000, 44100, 48000, 50000, -- 2.39.5