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 01B8E47CA9D for ; Fri, 2 Oct 2026 10:09:39 +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=1790935780; cv=none; b=tzBMBr/ZoOLfP9olDQpMbrYWILhddab/S2zoLlub/A1yPS0SOb9jAHEf96ro70AzJ/kaxB55jAyKQkyfgUL1wM5mmrAonwBrmJ7t3YA/V/nzy0lamF/QSXp2hsVPXN6MRO542uBRJpD/mlTK4z2c8azZTqU0ATf4r6ZMdYslCaM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790935780; c=relaxed/simple; bh=kTIjevvHnI6tk3I7bdraP1aqxwTnNibc6cViojCA4r0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=YSrxNEAjilywuj1eRK+wBjP5/+kIRBe+ZrZFipz2jr9IopZhJ15qbl+eI3OO54rk1gX+TgMMtgtGtBGlKUyIIhjEe0PB1ZIEhpI5I3tr4NFNNGcQBJSen708NQRWFrN1wRobLegOJ1l2pGrRSZ+7sp5d9uLBWGdfMr/cBIndzU4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=YhVvlZIm; 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="YhVvlZIm" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C85DA1F000FF; Fri, 2 Oct 2026 10:09:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790935778; bh=kTIjevvHnI6tk3I7bdraP1aqxwTnNibc6cViojCA4r0=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=YhVvlZImIxqbuB1Yq+sA//Rjnrhz17zbePIJ3Hk12l5kR818rurMHr0iK1fKiEIN4 +3SC+5eCeFgnA5mccvC/WsywRCPcTINbKsGABNrWkQmRL5z816D6nk3pVcta6jXMKD kQqL/rJZ1VIVxJl1oLK+V5U4VJOe1Q5W4ZfPCD/ppDm1g3oYiCeomoXB2l7zGoktNW ATyLovjbAJmTGV4MiVzlVezyw/JrrU1QS2iOvBeque3nEnazbzCiiupN2T8NI3D0TY dpvEcpS/8dYMSr00RAL3b3PfrnQu1MrTRMtgUXjUBfXaOvZfMAAHxuY+/VQgpJS6kX NurVf28Zra+Ag== Date: Fri, 2 Oct 2026 11:09:33 +0100 From: "Lorenzo Stoakes (ARM)" To: "David Hildenbrand (Arm)" Cc: Nguyen Ngoc Thang , akpm@linux-foundation.org, liam@infradead.org, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, peterx@redhat.com, dave.hansen@linux.intel.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, syzbot+49b1021becba70c1f3f6@syzkaller.appspotmail.com Subject: Re: [PATCH] mm: don't ioremap COWed anon pages in generic_access_phys() Message-ID: References: <699ae98c.050a0220.340abe.0d31.GAE@google.com> <20261001152524.171115-1-ngocthang2710.1999@gmail.com> <32fe40e2-854a-47ec-9d95-93e23f9a7af4@kernel.org> <9d43234f-93cb-4c86-a2a6-a3cdebf48f3b@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9d43234f-93cb-4c86-a2a6-a3cdebf48f3b@kernel.org> On Fri, Oct 02, 2026 at 12:04:27PM +0200, David Hildenbrand (Arm) wrote: > On 10/2/26 12:02, David Hildenbrand (Arm) wrote: > > On 10/2/26 10:38, Lorenzo Stoakes (ARM) wrote: > >> On Thu, Oct 01, 2026 at 10:22:29PM +0200, David Hildenbrand (Arm) wrote: > >>> > >> > >> Sorry to say this looks schlopped. > >> > >> This guy has sent 10 series across 6 subsystems over ~21 hrs: > >> > >> https://lore.kernel.org/all/?q=f%3Angocthang2710.1999%40gmail.com > >> > >> Nguyen - please do not flood the kernel with patches, and please use the > >> Assisted-by tag for generated content. > >> > >> The original code you submitted is really not great even if the issue may > >> be valid. > >> > >> So I'd say somebody from the core team should take over this if we want to > >> come up with a patch. > > > > Yes, I'll take care of it. > > > > [...] > >>> > >>> Signed-off-by: David Hildenbrand (Arm) > >> > >> This looks reasonable but I hate that we have 'special' CoW overrides like > >> this :) > > > > After sending this yesterday, I concluded that we can do this cleaner: just have > > > > bool normal_page; > > > > (naming suggestions?) > > > > that express that this is something refcounted with a struct page, like > > documented for vm_normal_page(). > > Hmm, have to think about that once more, regarding VM_IO and if there are some > cases that would actually have to work in generic_access_phys(). Well, my series at least makes it easier to reason about VMA_IO_BIT! Though not sure if it really touches PFN map cases specifically. > > -- > Cheers, > > David -- Cheers, Lorenzo