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 338013F104B; Thu, 15 Oct 2026 19:47:52 +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=1792093674; cv=none; b=EEycyNS2ITosLmHG8DzVW/tYdmrO20LusgIhfMcooto2CnXbu9XugVqHlzhxhbu0bPVEMZI2ds55uZjRsa45CqJ9tS/qCY+v2dbeJYsK2S8znvxE8m5Yw5E9k0Eggs5vhtediir+DRIYc2XqAdCw2Oz7hORJp4xTXNslhueffrg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792093674; c=relaxed/simple; bh=U4Q50Bch/7DY2meSVUid+sAQm6zjGxwuEGe2l2WAHzg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=eq1Ydtv1d9VGR22Mnih2vpFDMWYcrvFPSO1eK3e2lNaWFaCR5qcVtecPPVueVaneHYeCG12gzUizNtG1+uK4xoW0s5m1559Mec7MOHXnukXPsy2u9kTeXsjagoVJrztYRyc+R0iqGpA87N+hHUSaQRvAR4wMvMXBJgBp4gA4wu4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ThWtpvf6; 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="ThWtpvf6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F00CC1F000C4; Thu, 15 Oct 2026 19:47:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792093672; bh=V9lVAl0inOJKZISTRP7bv977o2J5aqss+rBQ8yoS51c=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=ThWtpvf6zsTR30bHJIEGafp2NXw3++Q+jHmYCqK53yM75cv5dhwRcvhB0Jcf9rGbw U4DIZQU8vzu+emd6urqBH0QG5KI1aEUnl9Ol9zdAdBbZTollbVlRykDUNmhos+QAU1 3Zj35yoE2B5rAlJ/+JXrWAOX+/qgUbR0B5qgBTLOZ3O9kEEjQC10STGDfwe9/EmXSc p16Pi8Ly4hQClJGe5OLe+CL6T94vALAS7lAL+j+99CkiV78DtHicCG7MWw/cD492/1 n9Uh7WftNS1kdvfUD3l2OIDjTlbJOVCD5zHGTSp3tEstj5OTUYVQMowVaracNTNkjm LTWyG8haewf5w== Date: Thu, 15 Oct 2026 20:47:45 +0100 From: "Lorenzo Stoakes (ARM)" To: "David Hildenbrand (Arm)" Cc: Andrew Morton , "Liam R. Howlett" , Vlastimil Babka , Jann Horn , Pedro Falcato , Muchun Song , Oscar Salvador , Miaohe Lin , Naoya Horiguchi , Adam Litke , Mel Gorman , Rik van Riel , Peter Xu , "Kiryl Shutsemau (Meta)" , "Mike Rapoport (Microsoft)" , Josef Bacik , linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH 08/10] mm/hugetlb: tolerate UFFD_WP markers outside uffd-wp VMAs Message-ID: References: <20261015-urgent_fixes-v1-0-42796911043b@kernel.org> <20261015-urgent_fixes-v1-8-42796911043b@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: <20261015-urgent_fixes-v1-8-42796911043b@kernel.org> On Thu, Oct 15, 2026 at 06:07:14PM +0200, David Hildenbrand (Arm) wrote: > UFFD PTE bit handling is a bit like swiss cheese, in particular with > recently added RWP mode. Having uffd-wp markers outside uffd-wp VMAs > already confused this code in the past and resulted in uffd-pte bits > confusing other code later. > > Let's play safe and just ignore these markers in hugetlb_no_page(), not > silently propagating the uffd-wp PTE bit. > > Fixes: 2d427bb01639 ("mm/userfaultfd: add RWP fault delivery and expose UFFDIO_REGISTER_MODE_RWP") > Cc: stable@vger.kernel.org > Signed-off-by: David Hildenbrand (Arm) Seems sensible so: Acked-by: Lorenzo Stoakes (ARM) > --- > mm/hugetlb.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c > index ba6860b9b7f4c..1548a6156206b 100644 > --- a/mm/hugetlb.c > +++ b/mm/hugetlb.c > @@ -5939,8 +5939,11 @@ static vm_fault_t hugetlb_no_page(struct address_space *mapping, > /* > * If this pte was previously wr-protected, keep it wr-protected even > * if populated. > + * > + * TODO: fix all cases where uffd-wp markers remain in VMAs that are no > + * longer registered with uffd. > */ > - if (unlikely(pte_is_uffd_wp_marker(vmf->orig_pte))) > + if (unlikely(userfaultfd_wp(vma) && pte_is_uffd_wp_marker(vmf->orig_pte))) > new_pte = huge_pte_mkuffd(new_pte); > set_huge_pte_at(mm, vmf->address, vmf->pte, new_pte, huge_page_size(h)); > > > -- > 2.43.0 > -- Cheers, Lorenzo