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 1440E4F797D; Mon, 12 Oct 2026 21:03:27 +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=1791839011; cv=none; b=JuMKxsvcYSDaD4HPEat0fyRDHh0GSq2kEeM80PXlH6U2OVWKXDG5fSKlGqTsTGuf3AknwyMlwEjFKypH3aWSriMP55VCvPVoSDS5Y79Fw3bg+DzElgw5sjsQPt6Qs61KAuHj/tNwu5BuzELKYmNM1YWrGAEnDnogD5blpm3YLWE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791839011; c=relaxed/simple; bh=ZUVh6R/51tY7aeu+dhEQl3dGFVx1Te0WET1p5rWyZMI=; h=Message-ID:Date:MIME-Version:Subject:From:To:Cc:References: In-Reply-To:Content-Type; b=Sbre9XtlquH2BAZYDUpsZRXp1YtxKLamny70HmQCqF5TofOKZc13nTjGYhXd31B9DYrLoJdEVSwnEM0AdIyW6QVxQz2/XU5pSYKZpVcRvIKKSUMGrQcZXfXvVdtYKDEvnZF6+kC7aiNg1VocWANSsfpt3mnwaVzELug4nFyJ9Lo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=iwa4zYia; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="iwa4zYia" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4196C1F0089B; Mon, 12 Oct 2026 21:03:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791839007; bh=8a9guZQ9UXhmWtlczU1xVFFTkDdI91mnDaX9njUfUDA=; h=Date:Subject:From:To:Cc:References:In-Reply-To; b=iwa4zYia+5w/t/XiWlULLwwMV7DmTgBMmyVF8U6tpQKGm4BI9sgOrr6xXopzh4eee 2glTihabvgLw0LmaL9pHCbZ2f9EOiXAfjmBBSCwwZzkdLm93rCWYJQ6nU3gbQ7y7hM 7EawWNKw8PrMWCyeRu6YhDFDZMR9b+kMdZyqsFJ6BjzNSfWzit5Uba+OOzirdFFqUc xKmQl36xMYAscXx7Yi5/4hfkGy83vdEtplRm/nQUx08umZV/QTw8BsTh7uVc7ABTCf tJ7M5pa2ETketAJBIDNuK9CtVXQAeyb10KYuTo5TPcafJZ7gTdAGTcIrPCiWcHA1Gi wJmpD9ghvu9rQ== Message-ID: Date: Mon, 12 Oct 2026 23:03:18 +0200 Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net-next v6 2/8] ipc, msg: Account msg_msg allocations with GFP_KERNEL_ACCOUNT again Content-Language: en-US From: "Vlastimil Babka (SUSE)" To: Kees Cook Cc: Christian Brauner , Jan Kara , Andrew Morton , Roman Gushchin , Johannes Weiner , Michal Hocko , Shakeel Butt , Muchun Song , cgroups@vger.kernel.org, linux-mm@kvack.org, Pedro Falcato , Kuniyuki Iwashima , linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org References: <20261006092030.got.500-kees@kernel.org> <20261006092035.166776-2-kees@kernel.org> <38befa8c-3885-44eb-813c-0ee34cd55248@kernel.org> Autocrypt: addr=vbabka@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 10/12/26 19:55, Vlastimil Babka (SUSE) wrote: > On 10/6/26 11:20, Kees Cook wrote: >> Since commit 734bbc1c97ea7 ("ipc, msg: Use dedicated slab buckets for >> alloc_msg()"), alloc_msg() allocates with GFP_KERNEL, and a msg_msg is >> accounted only through SLAB_ACCOUNT on its bucket caches. With >> CONFIG_SLAB_BUCKETS=n, kmem_buckets_create() creates no caches and >> kmem_buckets_alloc() is a GFP_KERNEL kmalloc() from the general caches, >> which do not account it; the same happens when kmem_buckets_create() >> fails. Either way, the allocation is not charged to the sender's memory >> cgroup. >> >> Allocate with GFP_KERNEL_ACCOUNT again, as before that commit. Memcg >> charges such an allocation in whichever cache serves it, so drop the >> SLAB_ACCOUNT, which no longer adds anything. >> >> Build tested ARCH=x86_64 defconfig with GCC 16.2.0, with >> CONFIG_SLAB_BUCKETS as y and n. >> >> Fixes: 734bbc1c97ea7 ("ipc, msg: Use dedicated slab buckets for alloc_msg()") >> Assisted-by: LLM >> Signed-off-by: Kees Cook > > Could we, for the purposes of a backportable fix, just have both > SLAB_ACCOUNT and GFP_KERNEL_ACCOUNT in place? That should do the right thing > regardless of CONFIG_SLAB_BUCKETS state, no? BTW we're thinking to add 1+2 (once this part is clarified) for 7.4 (with stable@ for patch 2). But for the rest we'll have to target 7.5 as it's only a week to the 7.4 merge window now.