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 D8485367B8E for ; Sat, 15 Aug 2026 06:18:53 +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=1786774735; cv=none; b=noBnc9ckDI/44TB/C+74gsrSxeYnJLnEm9Jp848pJ7v5q3zsXOzgUZO41n1V2uJNqrT0l53p6Qg1kmae8EiAPpUB/eeMQCzzYtBXTtpq2ZVmHRWjMkPDdy2DG1oGQwL7PeLh89BJlhvScremhVEs/XIUdOMQgVyJb6v1vLDMp2U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786774735; c=relaxed/simple; bh=mSxJxRlMslEbmQLVXGLNNm49ECafyWkzWG5EIjaSlbg=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=twxQUOAkTjWWmhMakr8Fz3CT9TRzZUSm8uESQaFmkFC7Qfu4c5WZeLwo+DtCArqJ7u4P6DHkrwkWaemKw6lwgX73Zrz0zkOeKgNk3iZLELMho60iIi+zp1c62u4wYpjNy8qVtu0iR4Yzu5N+gEpbfyo+wOx5jtynbOLjErp35gI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=KKDK14OE; 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="KKDK14OE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3AF5B1F000E9; Sat, 15 Aug 2026 06:18:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786774733; bh=J7iyJo99ils5CiZsgmM+aCuTYZvOEEoyBtzH7ikfwEw=; h=From:To:Cc:Subject:Date:Reply-To; b=KKDK14OE6x/NyBjFr32A4hLiYljdfaoI2yccit1NWclKOXIEceq7KScUMdOvzw7q1 EkdMa3Hg/+dfdeeThLPvy0tlhaxlZbQbsbuCpG00bGOQRUVHXVABweHGkv/OhuFGyP q2rugnFUZj+QJrbLioygIVSbaf3I/62VFurCrfs0= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-72215: MIPS: DEC: Ensure 32-bit stack location for o32 prom_printf() Date: Sat, 15 Aug 2026 15:04:54 +0900 Message-ID: <2026081546-CVE-2026-72215-116e@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=5397; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=ogDTqjNfoMKTMQ8DgTMMfs9441SuheV0DEseXFE59LE=; b=owGbwMvMwCRo6H6F97bub03G02pJDFkNDKdKjfvsxGKmvs2elq3Z8WH9LW5rqe7c7LqjUxcnX tnsJvS9I5aFQZCJQVZMkeXLNp6j+ysOKXoZ2p6GmcPKBDKEgYtTACai/oxhwaLOzukn+gUmWd+4 wTDp51SumMhWPob5JbNnT7hvHvrWlWvrPffSPf+8n8nYAwA= 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: MIPS: DEC: Ensure 32-bit stack location for o32 prom_printf() In 64-bit configurations calling any firmware entry points from a kernel thread other than the initial one will result in a situation where the stack has been placed in the XKPHYS 64-bit memory segment. Consequently the stack pointer is no longer a 32-bit value and when the 32-bit firmware code called uses 32-bit ALU operations to manipulate the stack pointer, the calculated result is incorrect (in fact in the 64-bit MIPS ISA almost all 32-bit ALU operations will produce an unpredictable result when executed on 64-bit data) and control goes astray. This may happen when no final console driver has been enabled in the configuration and consequently the initial console continues being used late into bootstrap, or with an upcoming change that will switch the zs driver to use a platform device, which in turn will make the console handover happen only after other kernel threads have already been started, and the kernel will hang at: pid_max: default: 32768 minimum: 301 or somewhat later, but always before: cblist_init_generic: Setting adjustable number of callback queues. has been printed. It seems that only the prom_printf() entry point is affected. Of all the other entry points wired only rex_slot_address() and rex_gettcinfo() are called from a kernel thread other than the initial one, specifically kernel_init(), and they are leaf functions that do no business with the stack, having worked with no issue ever since 64-bit support was added for the platform back in 2002. To address this issue then, arrange for the stack to be switched in the o32 wrapper as required for prom_printf() only, by supplying call_o32() with a pointer to a chunk of initdata space, which is placed in the CKSEG0 32-bit compatibility segment, observing that prom_printf() is only called from console output handler and therefore with the console lock held, implying no need for this code to be reentrant. Other firmware entry points may be called with interrupts enabled and no lock held, and may therefore require that call_o32() be reentrant. They trigger no issue at this point and "if it ain't broke, don't fix it," so just leave them alone. The Linux kernel CVE team has assigned CVE-2026-72215 to this issue. Affected and fixed versions =========================== Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 5.10.261 with commit 9cd4a8ed12d2a6313592e43c14cca5eca6717bee Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 5.15.212 with commit 3394757c5d3970ab36d2aafa6dd40952b43f0d16 Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 6.1.178 with commit 1ed18b5c3be9657fe288fa4dae0bef2470598683 Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 6.6.145 with commit 27857db30c98583e12dd8d939ba2370bce08a5be Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 6.12.97 with commit d828bca84311e278093e60b2864a54f4bbb0c2ad Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 6.18.40 with commit d3fd2d358df0ca712183509cbbed6a16bde1d17e Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 7.1.5 with commit 3ae86630b94f72bf4012c6322f81f622dc4fdf24 Issue introduced in 2.6.12 with commit 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and fixed in 7.2-rc1 with commit 5ff79e8bdc75db51e30298a75939e2308e7658e0 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-2026-72215 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: arch/mips/dec/prom/init.c arch/mips/include/asm/dec/prom.h 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/9cd4a8ed12d2a6313592e43c14cca5eca6717bee https://git.kernel.org/stable/c/3394757c5d3970ab36d2aafa6dd40952b43f0d16 https://git.kernel.org/stable/c/1ed18b5c3be9657fe288fa4dae0bef2470598683 https://git.kernel.org/stable/c/27857db30c98583e12dd8d939ba2370bce08a5be https://git.kernel.org/stable/c/d828bca84311e278093e60b2864a54f4bbb0c2ad https://git.kernel.org/stable/c/d3fd2d358df0ca712183509cbbed6a16bde1d17e https://git.kernel.org/stable/c/3ae86630b94f72bf4012c6322f81f622dc4fdf24 https://git.kernel.org/stable/c/5ff79e8bdc75db51e30298a75939e2308e7658e0