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 19A624A0912 for ; Thu, 24 Sep 2026 15:11:43 +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=1790262704; cv=none; b=dfz8c+IHHi6APJ/dzS8sPWgT69sDZKq9CMVMRxUFTyNR3sfTjcaunqotcOp+Rlnl4kG6f/Da6VWRTv3GcLcA71qkPftZw59Vy81bCKubXjHOdt1eqDMxpWWSZ/FwNecUamnwQn0gbRUhWTW42Jr7N1ETSBUNdKCwIK9uByUexUs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790262704; c=relaxed/simple; bh=p5vvxluboLZZeu9yTWWyScm2Kptk1SRKWsT92d+sH7E=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=FzDLDUSNADzPJQonYFJ8Y26NI4eCOaDZAepauSbrBbZ2zQqAVfXJnZWw+voD6unD7Mj3J+ybFprx77bHfy1szA6bcUD+Sg3c/ibY+pOeTdx4Lm2eIBKfJxHoxtHMPKhksDMT3+XDeVNnaV/GnuOwUrqNUG/ECKbDPqSMxJOVm6c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Ouoe+zeh; 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="Ouoe+zeh" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F1F231F000FF; Thu, 24 Sep 2026 15:11:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790262702; bh=quxmFQyUB2aUlhfupCG+4Nfx2o7fPnZ82ncMw4JuBFo=; h=From:To:Cc:Subject:Date:Reply-To; b=Ouoe+zehMn0Fc4JTBB+zM9rB2r59ziAjtlrxf2CnS9GBelMgRzk4wGM7Z/GwNGocj C9WSRr/sPpW2Xe8rUEnJrrN9Yl5jbeZ1U8F3dD5OqEArRWI2Gg2Kln+Fn8Acokv/cn nnS9iGKhvxcmEnKPthRFA0dn5LjLrfDeK47yYKkc= From: Greg Kroah-Hartman To: linux-cve-announce@vger.kernel.org Cc: Greg Kroah-Hartman Subject: CVE-2026-93218: mm/huge_memory: skip device-private PMDs in madvise_free_huge_pmd Date: Thu, 24 Sep 2026 17:10:54 +0200 Message-ID: <2026092445-CVE-2026-93218-bed2@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=2766; i=gregkh@linuxfoundation.org; h=from:subject:message-id; bh=G2qnbb5bC8GRgsosE6YwqYs0riWWqO8hYbLhMyx379U=; b=owGbwMvMwCRo6H6F97bub03G02pJDFlbbUsvzX/qZfzLbcVBo4hO1rDLc+3MPK4em7tXbu7yD wbhFVFnOmJZGASZGGTFFFm+bOM5ur/ikKKXoe1pmDmsTCBDGLg4BWAi210ZFqz6ZVuaW/Xp3JOE I/9DY49fmSBUZsMwP6Gk6NHbxy4FbYcLZTlLGTZWMs6eAAA= 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: mm/huge_memory: skip device-private PMDs in madvise_free_huge_pmd madvise_free_pte_range() checks pmd_trans_huge(*pmd) unlocked, then madvise_free_huge_pmd() takes pmd_trans_huge_lock(). pmd_is_huge() returns true for a device-private PMD, so orig_pmd can be device-private and enter the !pmd_present() branch. Skip device-private PMDs in that non-present branch and continue to out before calling pmd_folio(). Downgrade the check to VM_WARN_ON_ONCE() so an unexpected PMD softleaf logs a warning rather than panicking. Drop the thp_migration_supported() guard: it expands to IS_ENABLED(CONFIG_ARCH_SUPPORTS_PMD_SOFTLEAF), and both pmd_is_migration_entry() and pmd_is_device_private_entry() already return false when that config is not selected, so the guard suppresses only the case where the warning would already be silent. Potential trigger: an HMM-based GPU driver races with madvise(MADV_FREE): migrate_vma_pages() flips the PMD to a device-private entry between the caller's pmd_trans_huge() check and the callee's pmd_trans_huge_lock(). The Linux kernel CVE team has assigned CVE-2026-93218 to this issue. Affected and fixed versions =========================== Issue introduced in 6.19 with commit 368076f52ebeecd33e10a9f80905d7508b6b6149 and fixed in 7.2.4 with commit 5e3026bf736498115884d6c7bd0308ba29e0474c Issue introduced in 6.19 with commit 368076f52ebeecd33e10a9f80905d7508b6b6149 and fixed in 7.3-rc1 with commit ce579dcf730ce5ed8043a5eeea18a3e6706a97e5 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-2026-93218 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: mm/huge_memory.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/5e3026bf736498115884d6c7bd0308ba29e0474c https://git.kernel.org/stable/c/ce579dcf730ce5ed8043a5eeea18a3e6706a97e5