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 ADA7F19F424; Mon, 4 Aug 2025 00:40:34 +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=1754268034; cv=none; b=tn9yV5gmODB1PA12N9Hp5xddWS0D1uUmzL9ZOWrmLAeS8Gg28UaJl21gJy31pphNXenhp97Fdk8rg2yaR0KjFqvcBCzo5SAJaFqb9nB9qp/S6AvS/e4Z9KggaG4W49Xk7yzlNcxW1YlmL3dr6+N9isH5op6zeIP06KrtTJh8myw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754268034; c=relaxed/simple; bh=d4JYMMms2bOKKEZGyWxock+tBH9efGvgCLZWSgJOcZA=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=Mt2n/pU+DjkIfdvG9F7YG3MfwrhpSyn3QMKAUXoNQuOS2DodNhgaYXARiKTYSrt3h4AREpf9rmwAyopw9YHCg71XT7VsqDXPMK0ErKL6nJEKtSxWESW7e52fOjTZmZactdMK4u+EUaIKtWuCHUnhbgkY8j+NZxhzYinvLiwaktU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=rhy4FmKC; 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="rhy4FmKC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E3C11C4CEF8; Mon, 4 Aug 2025 00:40:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1754268034; bh=d4JYMMms2bOKKEZGyWxock+tBH9efGvgCLZWSgJOcZA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=rhy4FmKCRrue2U824NKRpd/Ta01smRWg29hwCTBjN2VR5HCuZ9ZIm7GHQsQuAuAx7 iQ2kbPy2KVWEWimdKx9ofFhmFdHjcotU9T133JnCG1N+y/rwMMRTuJbv4rc3kwkHps fWcegEWfxH8t3uQg1OiNKbTIKSonNLaiBMgkdEfbD+IbUn6Cu4F30w7duWRPMuuNjN yftilknzBMQyG/s4K01+dxZWqeWDbEpx+E8W0IQjRmchW8w7eMWT5osCe3whrx0DAh vqia1ZmP+eTGNEB573g4GidKxYoCNq4MDnE8jyyv4/dwgTL2GaZmvPejNsP7zuksF9 kYR4wfUFEiHCw== From: Sasha Levin To: patches@lists.linux.dev, stable@vger.kernel.org Cc: Cristian Ciocaltea , Takashi Iwai , Sasha Levin , franta-linux@frantovo.cz, lina+kernel@asahilina.net, livvy@base.nu, sstistrup@gmail.com, s@srd.tw Subject: [PATCH AUTOSEL 5.15 42/44] ALSA: usb-audio: Avoid precedence issues in mixer_quirks macros Date: Sun, 3 Aug 2025 20:38:47 -0400 Message-Id: <20250804003849.3627024-42-sashal@kernel.org> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20250804003849.3627024-1-sashal@kernel.org> References: <20250804003849.3627024-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-stable-base: Linux 5.15.189 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 5eccc8af839f..03cba220fff1 100644 --- a/sound/usb/mixer_quirks.c +++ b/sound/usb/mixer_quirks.c @@ -2132,15 +2132,15 @@ 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 @@ -2149,9 +2149,9 @@ 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