From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 41AF630DEA6; Sat, 12 Sep 2026 16:00:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789228825; cv=none; b=JTJaIqEwjt+awJETQiOrKiMdc+mNi3ClqmTk/JjIvAmxv9IKUHAJUU/hLM8BLJ8rd7p6fGA+xfRsvd6EKEiWzWsVek8hKPklUi3IWsUhvBDcDR4U5onJMSVFcsUJ3OoXTYBer9d+bakdryX8595jX8sPieabHOE3rJt3h0G7O58= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789228825; c=relaxed/simple; bh=hD5KxNaroYL88ukJeNOYP0eYrtwC3Ej8wdtkPBMOlVk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=sUAf/Caf6676wE/Qg/Q7/HBO16X467G7unSNC+Rw2aunhzb1zRZnQjS0Bn+XD3gtA4ucuoO7eCf/LbtFLNS3hndhFeAauXHpfJo6RxAAQU9gaOZ5658FW09xOugD21lokGMSL05/qClsMAMboD2+I/l5o4TyBJG9/1kiYW/yILY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=G2kbXsVL; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="G2kbXsVL" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1559D1F000FF; Sat, 12 Sep 2026 16:00:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789228824; bh=hhwAy094qKYn9G2HMtOGbwNlpOTajgnsxpJZnsC7rpk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=G2kbXsVLREPp68ZHBKrGQE8ae0fELqODCY9VaChSrY0SqRonE5shNf2dMjDYTs79W 70WW/APBlWQvJXABUF+SPBpsY/G0+fP8jDzMkWZUGtTRg/UaPkHpfhQHNerOocsT9U MwT8EUWIFA7GQ4JBw+RhYXCU3LVnoxQy0ciJ75EY= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Harry Wentland , Melissa Wen , Daniel Wheeler , Alex Deucher Subject: [PATCH 6.1 0421/1191] drm/amd/display: avoid divide-by-zero in __is_lut_linear() Date: Sat, 12 Sep 2026 08:52:29 +0200 Message-ID: <20260912065557.697241555@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065548.086904252@linuxfoundation.org> References: <20260912065548.086904252@linuxfoundation.org> User-Agent: quilt/0.69 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 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Harry Wentland commit 4f40873f8a4107df2b9c8e68c947c4fd0cd519d2 upstream. __is_lut_linear() computes the expected value of each entry with expected = i * MAX_DRM_LUT_VALUE / (size - 1); If it is ever called with a single-entry LUT, size - 1 is zero and the kernel takes a divide error (#DE). A LUT with fewer than two entries cannot describe a linear mapping anyway, so return false early instead of dividing by zero. Fixes: 086247a4b2fb ("drm/amd/display: Use 4096 lut entries") Cc: stable@vger.kernel.org Signed-off-by: Harry Wentland Reviewed-by: Melissa Wen Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c @@ -118,6 +118,12 @@ static bool __is_lut_linear(const struct uint32_t expected; int delta; + /* A LUT with fewer than two entries can't be interpolated and would + * divide by zero below (size - 1); it can't be treated as linear. + */ + if (size < 2) + return false; + for (i = 0; i < size; i++) { /* All color values should equal */ if ((lut[i].red != lut[i].green) || (lut[i].green != lut[i].blue))