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 049BF50C2B4 for ; Fri, 4 Sep 2026 16:53:40 +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=1788540821; cv=none; b=MGQPlE07CuqekW/BBXVz1FAK6YNg0pSoxeqEYmUHDurUw44ARQNVkMFCwpEOb8qE/2mYijtQAUlevulp2vMzxWahW9MfJ6zdl3qfEnO922LOT0d820nIt1It781/8woqD/VlMNuMB/y3R44iS4yj96AL+EUJ3byzAjU5+g4N4KU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788540821; c=relaxed/simple; bh=DIPENLasM1LQebz6Tj/JBILuHxk01HaQ4QN1ufkmsoM=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=LbeIrjgCEPwSWDMMIIkzmWNjr1AOGM1w9x59ohHoU+p4kOy7epU3G8x0tA8zuv57tG6769OdLQvGSEk2PnCj8kyv/WV1e6vdTuhKfuRnBwTSLNVxdZs35h/+8i3ch0iJBZJ4aqiKUpy2rlGo/wtD97H4P1fj0T+7frqLkMjql6Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=NT6qKTSX; 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="NT6qKTSX" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CC0D51F01569; Fri, 4 Sep 2026 16:53:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788540819; bh=yQldkLc6UHg/llzvgWhsMm3Yu5fY3maEnlVhdVA2x5Q=; h=From:To:Cc:Subject:Date:Reply-To; b=NT6qKTSXDnbRReRfxWP/BMiEnrHZdXhGSBGdHmPTFaGTfByQmO8++Km37yDG0q6mc LRUzPWPMKoVkVcScYJKLLN8IvIxEWJJ0B95nswEgaxn9gWexWhOdvzVdSGFW4vlxvM sbqyRv5HqtjXZDViU7ILMgm+dWX0oGR1vTNTuM/c= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-80886: serial: msm: Disable DMA for kernel console UART Date: Fri, 4 Sep 2026 18:46:53 +0200 Message-ID: <2026090438-CVE-2026-80886-3d9f@gregkh> X-Mailer: git-send-email 2.55.0 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=4322; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=cWp1MG4MYOsYdT+/6WGwojlSL6LmMRyGs8GupVKb8Ug=; b=owGbwMvMwCRo6H6F97bub03G02pJDFmzvr67sDXTb8rUkPnLpW1b/us6l7G2yy7aXnmVg+2Up sbSoN9WHbEsDIJMDLJiiixftvEc3V9xSNHL0PY0zBxWJpAhDFycAjARnqUM89TlFuZfkL908nnQ dZObCXmBsxNXfmGY7zgrafGk9RPii489e89Zkf0oVGXqaQA= 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: serial: msm: Disable DMA for kernel console UART At the moment, concurrent writes from userspace and the kernel to the console can trigger a race condition that results in an infinite loop of the same messages printed over and over again. This is most likely to happen during system startup or shutdown when the init system starts/stops a large number of system services that interact with various kernel code. When userspace writes to the TTY device, the driver initiates an asynchronous DMA transfer and releases the port lock. At the same moment, the kernel printk path might grab the port lock and re-configure the UART controller for PIO, without waiting for the DMA operation to complete. It seems like this collision results in zero progress being reported for the DMA engine, so the same text is printed to the console over and over again. For the kernel console, we want a reliable output path that will be functional even during crashes etc. So rather than implementing complex code to synchronize the kernel console write routines with the userspace DMA write routines, simply disable DMA for the console UART instance. Similar checks exist in many other serial drivers, e.g. 8250_port.c, imx.c, sh-sci.c etc. The Linux kernel CVE team has assigned CVE-2026-80886 to this issue. Affected and fixed versions =========================== Issue introduced in 4.4 with commit 3a878c430fd6eb4f8587f9ebd187f773bf85d1d6 and fixed in 5.10.261 with commit f58e568dc308c8e13f7730c8de2da5ed514e540d Issue introduced in 4.4 with commit 3a878c430fd6eb4f8587f9ebd187f773bf85d1d6 and fixed in 5.15.212 with commit bb4296de5b538b575978c588cb3738ab8524d01a Issue introduced in 4.4 with commit 3a878c430fd6eb4f8587f9ebd187f773bf85d1d6 and fixed in 6.1.178 with commit 6acea62738ed4cae6746483026706a773b44dad7 Issue introduced in 4.4 with commit 3a878c430fd6eb4f8587f9ebd187f773bf85d1d6 and fixed in 6.6.145 with commit abc1926c88c189e5d698b91ed6890e09ab5c321d Issue introduced in 4.4 with commit 3a878c430fd6eb4f8587f9ebd187f773bf85d1d6 and fixed in 6.12.97 with commit 2727744ccb5ca59090451451ee94f530b1be04a5 Issue introduced in 4.4 with commit 3a878c430fd6eb4f8587f9ebd187f773bf85d1d6 and fixed in 6.18.40 with commit d354716245192de2d203f2b35f22ab8dc13595e2 Issue introduced in 4.4 with commit 3a878c430fd6eb4f8587f9ebd187f773bf85d1d6 and fixed in 7.1.5 with commit e3b42e326f4f30efcdc90bad5f5ba37e1cd91a47 Issue introduced in 4.4 with commit 3a878c430fd6eb4f8587f9ebd187f773bf85d1d6 and fixed in 7.2 with commit 22dd2777e6c180e1c945b00f6d18550979436324 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-2026-80886 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/tty/serial/msm_serial.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/f58e568dc308c8e13f7730c8de2da5ed514e540d https://git.kernel.org/stable/c/bb4296de5b538b575978c588cb3738ab8524d01a https://git.kernel.org/stable/c/6acea62738ed4cae6746483026706a773b44dad7 https://git.kernel.org/stable/c/abc1926c88c189e5d698b91ed6890e09ab5c321d https://git.kernel.org/stable/c/2727744ccb5ca59090451451ee94f530b1be04a5 https://git.kernel.org/stable/c/d354716245192de2d203f2b35f22ab8dc13595e2 https://git.kernel.org/stable/c/e3b42e326f4f30efcdc90bad5f5ba37e1cd91a47 https://git.kernel.org/stable/c/22dd2777e6c180e1c945b00f6d18550979436324