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 6DEF0342501 for ; Wed, 13 May 2026 15:08:47 +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=1778684927; cv=none; b=Vj/Pc5fkURqO07Fj1RBfAwXGzyZmIohuJpWK6LRXYwQunNMw/E1JNxe+VL0VNYUVWIT+8E8hN+ySfDH+ZTpi8tEVtSdatB3T/ufZb3hV5HVBZgtd326CguT6lw+gc4KHdRNIJ8fDRjLAodyXsNw2W+PSyiWTI/4CT+NYazCJJ+A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1778684927; c=relaxed/simple; bh=tA3sRTZj8dg5NSZfc/A8ysEU7opVhn6hYnmbMN6FpsY=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=aPFN4mBJ+cie61IThuSxzSUgLsyjc3utHInEJDImRkhg6zI6L2D7U808hEmWbZpcJGYN0jHzkT1czMSu366N6axaF+Ci1hmNl/VKxhHIsOwKwZ7bXdXXe3nV/qQCX2F4hVUi9/GUVmuabnRdlhT+BJT/yTBfZN/yzCT86S6VoVM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=pQKXLpMC; 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="pQKXLpMC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 960BEC19425; Wed, 13 May 2026 15:08:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1778684926; bh=tA3sRTZj8dg5NSZfc/A8ysEU7opVhn6hYnmbMN6FpsY=; h=From:To:Cc:Subject:Date:Reply-To:From; b=pQKXLpMCYiooF3YZpZggy3cbXPkNz1PYDM/ooS4WKiMUo0Z+GTG7ZxylKGnTkuts/ dWVsDWK2rpfyOj4NGI4wO3RX2ocxrVobTPHYl6KwtI+ymPaO29z1q11HgBocrOJJ6E 7KgWoMHVmVVQXeh3flcIico0JKhVjVHvDi2xQy+o= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-43477: drm/i915/vrr: Configure VRR timings after enabling TRANS_DDI_FUNC_CTL Date: Wed, 13 May 2026 17:08:45 +0200 Message-ID: <2026051347-CVE-2026-43477-189e@gregkh> X-Mailer: git-send-email 2.54.0 Reply-To: , Precedence: bulk X-Mailing-List: linux-cve-announce@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3099; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=WVhMYdgGrh4nn89p0FS1mAYEJTdOKKBOd0fYBHLeqkc=; b=owGbwMvMwCRo6H6F97bub03G02pJDFksk/8fsl/5NubsQtOVf8TF7hjXWmS/Ko15lX7W5TOH5 IvN1abXOmJZGASZGGTFFFm+bOM5ur/ikKKXoe1pmDmsTCBDGLg4BWAiKosY5mm7P5nrLTYl+tub H/Wit/VfLFqvs49hfoLUk26d1uUFG6KuBnr9c34uvObjIQA= X-Developer-Key: i=gregkh@linuxfoundation.org; a=openpgp; fpr=F4B60CC5BF78C2214A313DCB3147D40DDB2DFB29 Content-Transfer-Encoding: 8bit From: Greg Kroah-Hartman Description =========== In the Linux kernel, the following vulnerability has been resolved: drm/i915/vrr: Configure VRR timings after enabling TRANS_DDI_FUNC_CTL Apparently ICL may hang with an MCE if we write TRANS_VRR_VMAX/FLIPLINE before enabling TRANS_DDI_FUNC_CTL. Personally I was only able to reproduce a hang (on an Dell XPS 7390 2-in-1) with an external display connected via a dock using a dodgy type-C cable that made the link training fail. After the failed link training the machine would hang. TGL seemed immune to the problem for whatever reason. BSpec does tell us to configure VRR after enabling TRANS_DDI_FUNC_CTL as well. The DMC firmware also does the VRR restore in two stages: - first stage seems to be unconditional and includes TRANS_VRR_CTL and a few other VRR registers, among other things - second stage is conditional on the DDI being enabled, and includes TRANS_DDI_FUNC_CTL and TRANS_VRR_VMAX/VMIN/FLIPLINE, among other things So let's reorder the steps to match to avoid the hang, and toss in an extra WARN to make sure we don't screw this up later. BSpec: 22243 (cherry picked from commit 93f3a267c3dd4d811b224bb9e179a10d81456a74) The Linux kernel CVE team has assigned CVE-2026-43477 to this issue. Affected and fixed versions =========================== Issue introduced in 6.16 with commit dda7dcd9da73c5327aef42b89f0519bb51e84217 and fixed in 6.18.20 with commit 8a7d29b8bda144d44e61df1b2705b1d4378f4e44 Issue introduced in 6.16 with commit dda7dcd9da73c5327aef42b89f0519bb51e84217 and fixed in 6.19.9 with commit bf9e3b6ffd76da38dd4961c65d80571b25bf10a5 Issue introduced in 6.16 with commit dda7dcd9da73c5327aef42b89f0519bb51e84217 and fixed in 7.0 with commit 237aab549676288d9255bb8dcc284738e56eaa31 Please see https://www.kernel.org for a full list of currently supported kernel versions by the kernel community. Unaffected versions might change over time as fixes are backported to older supported kernel versions. The official CVE entry at https://cve.org/CVERecord/?id=CVE-2026-43477 will be updated if fixes are backported, please check that for the most up to date information about this issue. Affected files ============== The file(s) affected by this issue are: drivers/gpu/drm/i915/display/intel_display.c drivers/gpu/drm/i915/display/intel_vrr.c Mitigation ========== The Linux kernel CVE team recommends that you update to the latest stable kernel version for this, and many other bugfixes. Individual changes are never tested alone, but rather are part of a larger kernel release. Cherry-picking individual commits is not recommended or supported by the Linux kernel community at all. If however, updating to the latest release is impossible, the individual changes to resolve this issue can be found at these commits: https://git.kernel.org/stable/c/8a7d29b8bda144d44e61df1b2705b1d4378f4e44 https://git.kernel.org/stable/c/bf9e3b6ffd76da38dd4961c65d80571b25bf10a5 https://git.kernel.org/stable/c/237aab549676288d9255bb8dcc284738e56eaa31