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 67428CA9ED0 for ; Mon, 12 Oct 2026 19:12:06 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 6D3086B0096; Mon, 12 Oct 2026 15:12:05 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 6839A6B0099; Mon, 12 Oct 2026 15:12:05 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 54C456B009B; Mon, 12 Oct 2026 15:12:05 -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 25AD16B0096 for ; Mon, 12 Oct 2026 15:12:05 -0400 (EDT) Received: from smtpin26.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay05.hostedemail.com (Postfix) with ESMTP id BB39E40F89 for ; Mon, 12 Oct 2026 19:12:04 +0000 (UTC) X-FDA: 85314919368.26.6B1A5D0 Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf07.hostedemail.com (Postfix) with ESMTP id 0186C40011 for ; Mon, 12 Oct 2026 19:12:02 +0000 (UTC) Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=BEu0ArYB; spf=pass (imf07.hostedemail.com: domain of ljs@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=ljs@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=1791832323; b=0Y6XfAo+wtnAI9zYeW2lF9fiJEcTjSl4XT/aZF7K8J+QU2Q2iJwNKb1KXXTiJZUsZTZoDO apMeolss7mdBZLF1UQhkqgkmBb8rwdBtmOwaxXt1Z4j8EILNgRsBFHg5QXFBnmSPpcRfPA h2xiyw+4mcsxEwYz/t/ui8JUNCNg6to= ARC-Authentication-Results: i=1; imf07.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=BEu0ArYB; spf=pass (imf07.hostedemail.com: domain of ljs@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=ljs@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=1791832323; 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=t5mO4SpyqVviWjSaaEv8n4NUJ8+LaAHDu09XG7kSbFs=; b=TvggT6QZ1QbR4th+RcSdlS1SQTX//tKYWRLfpvxbPbC3vN4/xiH9nnX+3/sPQ09Tqclw24 gJ9vZNJMii69ufy9valG/CTvuDMQ7qPOISf+wR5uA7ABEw93TR4G/dBlUEDzbOjPp3AVhH aaEReP1Dkwll092ryc3aOvI1b+nAbls= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 62F2460142; Mon, 12 Oct 2026 19:12:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 58B361F0089B; Mon, 12 Oct 2026 19:11:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791832322; bh=t5mO4SpyqVviWjSaaEv8n4NUJ8+LaAHDu09XG7kSbFs=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=BEu0ArYB5XZKL/22X+idpyNhILy00Ml5Fj2jTZ7Fk/4tKlvNrtbcuHyIbatS1i6+H EgraXbynE/kQHml4oxd8zg6gA+C0hu9dN4/bgco2QE++oQB5bH8DxThhNACrQfpLo5 XjczelQ46llI8hh5qdyeZlOGyGOojXJ0MYtBFM6yqvzpX+4jdT2meUTVQWDtflbCXM 6iF5pmWBFtkh91Se1FhzLeFVS17tfaVz+ddcjoVeEnKq4qW/b4a4Az4vnWO1vg7GEy PxJnHj6TKtLcX2c2xZZNIY6SbIQi0/ch6peXKK7YGg1Kjv6Q5wlicS2sXtSXi+SohG UEkXkdb5KImtQ== Date: Mon, 12 Oct 2026 20:11:27 +0100 From: "Lorenzo Stoakes (ARM)" To: "David Hildenbrand (Arm)" Cc: Andrew Morton , "Liam R. Howlett" , Vlastimil Babka , Jann Horn , Pedro Falcato , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jonathan Corbet , Greg Kroah-Hartman , Dennis Dalessandro , Jason Gunthorpe , Leon Romanovsky , Paul Moore , Stephen Smalley , Jaroslav Kysela , Takashi Iwai , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Eduard Zingerman , Kumar Kartikeya Dwivedi , Zi Yan , Baolin Wang , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Usama Arif , Kiryl Shutsemau , Doug Gilbert , "James E.J. Bottomley" , "Martin K. Petersen" , Simona Vetter , Helge Deller , Sebastian Reichel , John Hubbard , Peter Xu , Masami Hiramatsu , Oleg Nesterov , Peter Zijlstra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, Arnaldo Carvalho de Melo , Namhyung Kim , Mark Rutland , Rik van Riel , Harry Yoo , Juri Lelli , Vincent Guittot , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Will Deacon , "Aneesh Kumar K.V" , Nick Piggin , Arnd Bergmann , Muchun Song , Oscar Salvador , "Matthew Wilcox (Oracle)" , Jan Kara , Marc Zyngier , Oliver Upton , Catalin Marinas , Madhavan Srinivasan , Anup Patel , Paul Walmsley , Palmer Dabbelt , Albert Ou , Christian Borntraeger , Janosch Frank , Claudio Imbrenda , Alexander Gordeev , Gerald Schaefer , Heiko Carstens , Vasily Gorbik , "David S. Miller" , Andreas Larsson , Alexander Viro , Christian Brauner , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Gregory Price , Ying Huang , Alistair Popple , Chris Li , Kairui Song , Kemeng Shi , Nhat Pham , Baoquan He , Youngjun Park , Johannes Weiner , Qi Zheng , Shakeel Butt , Axel Rasmussen , Yuanchu Xie , Wei Xu , Chengming Zhou , Michal Hocko , Miklos Szeredi , Xu Xin , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org, linux-usb@vger.kernel.org, linux-rdma@vger.kernel.org, selinux@vger.kernel.org, linux-sound@vger.kernel.org, bpf@vger.kernel.org, linux-scsi@vger.kernel.org, linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-trace-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-arch@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, kvmarm@lists.linux.dev, linuxppc-dev@lists.ozlabs.org, kvm@vger.kernel.org, kvm-riscv@lists.infradead.org, linux-riscv@lists.infradead.org, linux-s390@vger.kernel.org, sparclinux@vger.kernel.org, fuse-devel@lists.linux.dev, Ihor Solodrai , Bert Karwatzki , Emil Tsalapatis Subject: Re: [PATCH v5 13/38] bpf: arena: mark arena_map_mmap() mappings VM_MIXEDMAP Message-ID: References: <20261009-b4-mmap-prepare-vma-flag-sanify-v5-0-923b70125b1e@kernel.org> <20261009-b4-mmap-prepare-vma-flag-sanify-v5-13-923b70125b1e@kernel.org> <5b8ef0ce-7429-4d74-b4da-a0561c59b1e2@kernel.org> <4124106e-c51e-4476-bd67-63e4641bf14a@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4124106e-c51e-4476-bd67-63e4641bf14a@kernel.org> X-Stat-Signature: eynz7texqq7bu56adbwysmufqi57obf1 X-Rspamd-Queue-Id: 0186C40011 X-Rspam-User: X-Rspamd-Server: rspam02 X-HE-Tag: 1791832322-103425 X-HE-Meta: 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 BmpwiHeC 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 P1rz9Yvb 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 bKBkSGra 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 pptq/cqw M/mHidO8Mip1t7pSXQEn5HCkVVXMmgqVzLi+1Hydw/4dQNwPQJrIh6KaTPDX81lWRxeDY+l1Eb7dm+SEbdC6qjiRRex/TZWjyHklc55P5/zAEIcn1rTalAF8J/b0ODoViUOskF5lbVOrD7lkWgljniHpYSuSgcuK7/h/tdRMUG5DCp9WVPaGlDmXsrHpvw5oRzo70+GJ7ZekJvfRNUdlKX2LzH4obDmrHOhqYHiCimCgrcntalIAj2vwYKQRNv5dbX8KKUgTIKfYJkyz54VZ+IfYfZKmG0o4bIRgkE9CTOeBlyVX9rbZbhhWT2eZoPn3B12C6Y6bYoZQkjJmtf9P/tZgikZpwFW50= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Oct 12, 2026 at 08:56:23PM +0200, David Hildenbrand (Arm) wrote: > On 10/12/26 17:55, Lorenzo Stoakes (ARM) wrote: > > On Mon, Oct 12, 2026 at 05:08:09PM +0200, David Hildenbrand (Arm) wrote: > >> On 10/9/26 20:04, Lorenzo Stoakes (ARM) wrote: > > > >>> diff --git a/kernel/bpf/arena.c b/kernel/bpf/arena.c > >>> index 7b6847200b43..b69fe5e34339 100644 > >>> --- a/kernel/bpf/arena.c > >>> +++ b/kernel/bpf/arena.c > >>> @@ -620,8 +620,9 @@ static int arena_map_mmap(struct bpf_map *map, struct vm_area_struct *vma) > >>> * clears VM_MAYEXEC. Set VM_DONTEXPAND to avoid potential change > >>> * of user_vm_start. Set VM_DONTCOPY to prevent arena VMA from > >>> * being copied into the child process on fork. > >>> + * This is a kernel page so set VM_MIXEDMAP. > >>> */ > >>> - vm_flags_set(vma, VM_DONTEXPAND | VM_DONTCOPY); > >>> + vm_flags_set(vma, VM_MIXEDMAP | VM_DONTEXPAND | VM_DONTCOPY); > >>> vma->vm_ops = &arena_vm_ops; > >>> return 0; > >>> } > >>> > >> > >> Historically, VM_MIXEDMAP really just means: can contain refcounted and > >> non-refcounted things. Everything with a struct page is refcounted. > >> > >> I think we are now changing the semantics to mean "maps kernel pages". I think > > > > Yes. > > > > It was sort of implicit before given insert_page() etc. but still really meaning > > that it _might_ be both. > > Yeah, it's in the name. Mixed: pfn and/or ordinary. Well the name is confusing as a great many users never mix anything, and it's far from obvious you need to set one. Anyway, one for later. Maybe a mask like VMA_NON_MM_MANAGED_MASK or something better than that... > > > > >> this is fine, but we really have to update the documentation (and possibly > >> rename this thing to something more expressive?) > > > > Yeah I completely agree. > > > > I will rename it, but I think that's best for 7.5 obviously! :) > > Yes. > > VM_PFNMAP / VM_MIXEDMAP - These contain kernel-mapped data which cannot be > reasonably reconstructed on page fault. > > the description is already pretty clear. just not that kernel-mapped pages > *must* use one of these. I think mixed map could do with a rename because it implies it _is_ mixed rather than could be. But again one for the future! > > (again, the ->fault thing returning allcoated kernel memory is nasty) Yeah added to my todo to fix that. Hateful. -- Cheers, Lorenzo