From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from ms.lwn.net (ms.lwn.net [45.79.88.28]) (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 2902E2DECDE; Sat, 6 Jun 2026 16:11:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=45.79.88.28 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780762288; cv=none; b=sg1Jg+sigccLJq+oRetqsqxooHMW6XFQjH+Fqk/pyT3iKhgm3IgHqYYkBF70FgyuU1Cp1QyjG9zC369slsd7Je9S/g0Ofl8KlXD6EZKpFePEyp6zcI2HolFWMfGrpfuOuFpa1g+W4bAZQPSimqw6+ZU0XrYZA19qt4Z84YrWN1c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780762288; c=relaxed/simple; bh=mb1PpEG8RYFB4Ga6Mdj4igPZk2VoQ3jfb68mA/FlnKw=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=GWRE3W5re6BC9hmHIUyeXsHhCa+RqzcTXvQMDWC8j+1UFJCE5ctalvRrl/A0WAPyWYT6I3KvRXxvXN43j2OIpkAsEhxniXIAmIb+zzDSPkzpiq3coZqWxYzSnpHQhDpBj3e3KKVCWqeNLlphi4qSiJMy4wXQdDtWpUZA6HanGNY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lwn.net; spf=pass smtp.mailfrom=lwn.net; dkim=pass (2048-bit key) header.d=lwn.net header.i=@lwn.net header.b=Zdl3qL0m; arc=none smtp.client-ip=45.79.88.28 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lwn.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=lwn.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=lwn.net header.i=@lwn.net header.b="Zdl3qL0m" DKIM-Filter: OpenDKIM Filter v2.11.0 ms.lwn.net 4EBC040E33 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=lwn.net; s=20201203; t=1780762286; bh=DqGXeDqpKIvvW3QQbyRaGwc6KekIm0MprRWgRPkr2tU=; h=From:To:Cc:Subject:In-Reply-To:References:Date:From; b=Zdl3qL0mTPsA6dWXrgZkxtue29RQ67FMWdoCbH7C1EURLFFPmbcbJZu3qW9J1lYYO xPfdGc3JATslC7hfgaVGhOLRgNZEtQxW/kfDlAWKh2f1wfxYzbHnb/pJZYxcsvDFGA 9p8smW9WhagTrBFUl12X65Fq4Rwwz/K5X6xpJcJMHY0+uMNE6qZqKsCYgHV4Aodc9d /JzuvNwAWkaobPXh4Qodlx0Yg7qhPqq0/Ob+yBMnECyWV/hbgToKIy/oIpeJUJjw2i 2Hgt/qtdbF95eGHxShpp//CGCUHOR1WOBvcT9u2FfLDo9jVlFnMLnO4bRI8513W69L HNABuMEWjFvTQ== Received: from localhost (unknown [IPv6:2601:280:4600:27b:67c:16ff:fe81:5f9b]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (prime256v1) server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by ms.lwn.net (Postfix) with ESMTPSA id 4EBC040E33; Sat, 6 Jun 2026 16:11:26 +0000 (UTC) From: Jonathan Corbet To: Mohammed EL Kadiri , Andrew Morton , Vlastimil Babka Cc: David Hildenbrand , Lorenzo Stoakes , Kees Cook , linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org, Mohammed EL Kadiri Subject: Re: [PATCH] docs/mm: document slab cache isolation with SLAB_NO_MERGE In-Reply-To: <20260606155856.15548-1-med08elkadiri@gmail.com> References: <20260606155856.15548-1-med08elkadiri@gmail.com> Date: Sat, 06 Jun 2026 10:11:25 -0600 Message-ID: <874ijfvec2.fsf@trenco.lwn.net> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain Mohammed EL Kadiri writes: > Add documentation explaining when and how to use SLAB_NO_MERGE to > protect security-critical slab caches from cross-cache heap > exploitation. > > The document covers: > - Criteria for identifying caches that need isolation > - How the SLUB merge mechanism works and what prevents merging > - How to verify merge status on a running system > - The cross-cache attack class with CVE reference > - Tradeoffs (memory cost vs security benefit) > - Relationship to CONFIG_RANDOM_KMALLOC_CACHES, SLAB_TYPESAFE_BY_RCU, > and the slab_nomerge boot parameter > > This information was previously undocumented, requiring developers to > read mm/slab_common.c to understand when SLAB_NO_MERGE is appropriate. > > Signed-off-by: Mohammed EL Kadiri > --- > Documentation/mm/index.rst | 1 + > Documentation/mm/slab-isolation.rst | 113 ++++++++++++++++++++++++++++ > 2 files changed, 114 insertions(+) > create mode 100644 Documentation/mm/slab-isolation.rst Thank you for working to improve our documentation. Did you write this with machine assistance? Please review our documentation and adhere to our markup conventions. For example, function names should just be function(), with no additional markup. Thanks, jon