From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 97687CA6012 for ; Fri, 9 Oct 2026 06:36:14 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 936ED6B00A0; Fri, 9 Oct 2026 02:36:13 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8E7326B00A2; Fri, 9 Oct 2026 02:36:13 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7D6516B00A1; Fri, 9 Oct 2026 02:36:13 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 5154F6B009F for ; Fri, 9 Oct 2026 02:36:13 -0400 (EDT) Received: from smtpin23.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay05.hostedemail.com (Postfix) with ESMTP id BD90840252 for ; Fri, 9 Oct 2026 06:36:12 +0000 (UTC) X-FDA: 85302128184.23.6D66F22 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf27.hostedemail.com (Postfix) with ESMTP id 3B7EE40003 for ; Fri, 9 Oct 2026 06:36:11 +0000 (UTC) Authentication-Results: imf27.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b="adm/PXte"; spf=pass (imf27.hostedemail.com: domain of kees@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=kees@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1791527771; b=0JOAH56NIqEmnoWq3tf4EYvApkgid8zknOaDZCt0SGrMerQLgJPq5mTTLfdspA5FRb8Edq 7DDHqaDdQYiBj76C27J/BskPr+6jE1jQO51WHcBk0UtCqPR+bZLwYKtiWzIMYAcK3vlCCq oaust4ZIyvrMna9bTeEmvgPb7ZpZOMg= ARC-Authentication-Results: i=1; imf27.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b="adm/PXte"; spf=pass (imf27.hostedemail.com: domain of kees@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=kees@kernel.org; dmarc=pass (policy=quarantine) header.from=kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1791527771; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=gDpTPyFrfxPK/Uf/lFR6lzmG1KtMFb1k0z6iyA57/Qk=; b=VTChfge1AdyBy6EBXzViz+pMPY+HN1QXlCJ9OFJur9rdaM8VmqAIUagrpkqcAzllyMjSFL 5viZ/T/P/opQUcts3YZAu30cKIOeFZUieW0qxetM1N1cymFVIJR5uAJPncEes1YqVAF6Wy 2EKj+IBDr36/sBpzHVVJ4sPs1roE9Y0= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 3458741824; Fri, 9 Oct 2026 06:36:10 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0E7D51F000FF; Fri, 9 Oct 2026 06:36:10 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791527770; bh=gDpTPyFrfxPK/Uf/lFR6lzmG1KtMFb1k0z6iyA57/Qk=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=adm/PXteCoY9Ji6saNhj4L6Dqguia+KG2/3Nr+/ar0UHgfEYUz2BGq6wjJLDGi6F3 liU8vicxy2gTOqC4yZ0W5OeGkkJJC0uPn5qOX1/HqutbBsxs3TigwAPxmIwOJzmQ6t nJ9Sn5WzLPXhkmfTQBgZ7He7WVdlb0idBiQIE27jcKbGTZ9QE5yYOtgsUds+hBZGoK bGoPuCSWqujD6cXwPoHslFO++VzLMCWxK29x5mF0jrnvRXkWgGGVihOsEr+E4lhcXg 76j+4XTX5LIPQ0B539LHeDrjQVMAD9e+yoPSzyE0uAxVqGBjuhgxQ2a9XcsGNk7BLn iGbpxQ869yG5w== Date: Thu, 8 Oct 2026 23:36:09 -0700 From: Kees Cook To: Harry Yoo Cc: Vlastimil Babka , "David S. Miller" , Andrew Morton , Hao Li , Christoph Lameter , David Rientjes , Roman Gushchin , Pedro Falcato , Kuniyuki Iwashima , Christian Brauner , Jan Kara , Johannes Weiner , Michal Hocko , Shakeel Butt , Muchun Song , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Willem de Bruijn , Jason Xing , cgroups@vger.kernel.org, netdev@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: Re: [PATCH net-next v6 0/8] net: skb: isolate skb data area allocations into a separate bucket Message-ID: <202610082331.853F0CBBA@keescook> References: <20261006092030.got.500-kees@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Stat-Signature: xcir9daxhmdjoncs7c4i66xd9wo856ph X-Rspamd-Queue-Id: 3B7EE40003 X-Rspam-User: X-Rspamd-Server: rspam02 X-HE-Tag: 1791527771-810254 X-HE-Meta: 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 tL3UlCLb ONzvcpdFmxEfehp+l/ojjTj12/KX9MZ7L+4my+RV2ZjMZuMnvO+gzocj9Q/QU+FH+veH1W/R3jHxZ73TUWHq37UsCfW7/sEKRAHsbd6QoJHdTocmHa70oTWlPzVaTAhHLtfHnlXKHf54p25caPkGiZ+p7aXO58kOrWD/ic9CUSmdBoHsr/uVKw/g4z1VakHlL4lyINcKRbYmvyvIYNR1GdElaT19vQUPi5HuJVtUK0gk/0LJA8WHrehwuQfqYQ6x15l1i Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Oct 08, 2026 at 11:25:13PM +0200, Harry Yoo wrote: > On Tue, Oct 06, 2026 at 02:20:26AM -0700, Kees Cook wrote: > > Hi! > > Hi Kees! > > Was hoping to say hi to you at LPC but I missed the chance ;) > Maybe next time. Safe travels! Hi! Yes, I kept trying to find you and Vlastimil but it never worked out. LPC is a non-stop hallway track usually. :) I will try again next year! > > So v6 goes back to mirroring the kmalloc cache's alignment, > > I might be missing something, but why is that a problem? > > For kmem_buckets users, the reason* to specify alignment is because > they might need less strict alignment than kmalloc. > > (*Perhaps it's nice to document that in the comment) > > However, because kmem_buckets can fall back to kmalloc on e.g. kernels > w/o CONFIG_SLAB_BUCKETS, it should be fine to fall back. No? > > Creating kmem_buckets with more strict alignment than > kmalloc doesn't make sense. > > > and drops the ctor and flags arguments for the same reason. > > Uh, for ctor and flags, yes. We can't have them in kmem_buckets. Yeah, and given that these two, I'd just prefer to keep it a direct mirror for alignment too and not allow for any configurability here: they are supposed to be direct stand-ins for the general cache. > Going thorough slab/for-next sounds reasonable to me once it gets > some reviews. Thanks! -Kees -- Kees Cook