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 AEC402F39C2; Sat, 12 Sep 2026 18:32:27 +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=1789237949; cv=none; b=sU4DzwMygjJYf/rHa2PFSB7AFg5u79Mij5+mjoj/+FTYCrekrI1ZzX3WpkRpcwEzCftJUN81F8V5jfZR3cWYgXzSsxfcThmMdR8tYPuiryKREBLSHqDNSGhaO2Mt/BJGG3z87MYFz49sDBJD/SgJzxWYPmGjGasgXk+FL7fAo0w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789237949; c=relaxed/simple; bh=WuEQek9BlpEun2LEhVik7pcfEXjReCYc6jlo9OOrTiA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=RSxHtTf97OumyCuYewwCMW1p0sF8NadwI3PZsgBv3wKlyldSeT+hdR1m8DWrgESYBS4ZmXpEa2tCkmy2G7JIuuFUDqsvyaeIPRvgYdV8oMmWwC07vsdGDBLKQx6PJ64RFRKT07aimdImSRj0EvI8bk1kzCajlm727BraZ2+0bww= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=j64Jffnv; 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="j64Jffnv" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 407E21F000FF; Sat, 12 Sep 2026 18:32:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789237947; bh=bBbtre/MfNGzBge3U3/D4mWhsWw/76+rbWuMKfW63v4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=j64JffnvvlqqvmH019CeKdheDLNcWsvuhUMxNo5SjvkbniGNmIxW3BHA/ovVP8xcx iGDA4ZR4RevhEiO7GDewBEmbi16gIwX6IQf7dbso/vsPGUi4OHjftVkxeIA3S+4JDo oZDuR20FgLMb7t0DELHcTOkfwhV5z/PuHaqPLew0= 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 5.15 363/935] drm/amd/display: avoid divide-by-zero in __is_lut_linear() Date: Sat, 12 Sep 2026 08:56:33 +0200 Message-ID: <20260912065535.135016882@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065526.833703348@linuxfoundation.org> References: <20260912065526.833703348@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 5.15-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 @@ -104,6 +104,12 @@ 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))