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 8570B511E99; Tue, 13 Oct 2026 21:01:29 +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=1791925290; cv=none; b=Mbo5I8w20XIUICh/5xlay94odRaJkOusO8q33ua22RW1CsUZy1g9iYPgjDWio4YXUummkw2virNqiAJ62XuK7YtlM21qlt2dj19nJguxUxkvvnwj9TGMnIGJDfnuYMD+XdbgNycgeYUur+fArnpKBKZpEng8S6c72rG6hEOIsEM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791925290; c=relaxed/simple; bh=sZBpQpUadceoBMH/ZvndmIicfOcoKzSaD702QVr/ELg=; h=Message-ID:From:Subject:To:Cc:In-Reply-To:References:Content-Type: Date; b=gAUOOxXzDszn4FFauV/Vq/rA0hwtvsa63BhnK91zylhBonWeKqK+TM5k89rKBKYFQhMU7Jow478Q86B+v1ydfs1HvHCKrrwXKWcu/yj8SJDgJi3VWwHJfayM5ioRJhP/C5AeB6pYLyLTgryMezKqheaiEYm/L9Jr1PWnZRDD8k0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=I5iyKOEG; 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="I5iyKOEG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9B3AC1F000FF; Tue, 13 Oct 2026 21:01:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791925289; bh=sZBpQpUadceoBMH/ZvndmIicfOcoKzSaD702QVr/ELg=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=I5iyKOEGDVO1a6Vo0mVKxSPizNMG81SiH8SYBx0pmjMVzO3El1dqQAabweqHcyfZB hl3uPuOGx5XVdBOsABwAn+r9u1ypBHUh2lepFtUKppIg6taJmaT96teJRo70st8I3t h9G1L6EaCJ5DrXL9BscLwdljlCJ/O7s3B1uVodPrvWKPzll397ce5v9ACJgfOCYg69 /PGAzIHJEbA8fQ4VQjgbvR/5Oj1EWdQnYpaZkfKge2NDFxfwa1Wz+Fj1rqwolYgX7/ aNCqAnOlDYctuOP33BKm7QjQeGNj/WUdknx4AeZVUaMVxOevxx2MwX1cIe9vZsriee oXsXoigbrc80Q== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v6 33/39] mm/madvise: use predicates for madvise(..., MADV_DOFORK) Reply-To: sashiko-reviews@lists.linux.dev To: =?utf-8?b?TG9yZW56byBTdG9ha2VzIChBUk0p?= Cc: linux-usb@vger.kernel.org, linux-rdma@vger.kernel.org, selinux@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-s390@vger.kernel.org, "Heiko Carstens" , "Vasily Gorbik" , "Alexander Gordeev" , "Christian Borntraeger" In-Reply-To: <20261013-b4-mmap-prepare-vma-flag-sanify-v6-33-1aa3c9b139f9@kernel.org> References: <20261013-b4-mmap-prepare-vma-flag-sanify-v6-0-1aa3c9b139f9@kernel.org> <20261013-b4-mmap-prepare-vma-flag-sanify-v6-33-1aa3c9b139f9@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 13 Oct 2026 21:01:28 +0000 Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: > Make it clear what we're blocking in MADV_DOFORK. Previously we simply > disallowed VM_SPECIAL i.e. mappings not managed by core mm, fixed mappings > and VMA_IO_BIT. >=20 > Now the invariant is established that mm-managed mappings may not set > VMA_IO_BIT, the VMA_IO_BIT check is redundant. >=20 > The rest is equivalent to testing for a fixed or non-mm-managed mapping, > i.e. a mapping which is not mm-backed, or hugetlb, which is specifically > excluded. >=20 > This was established by commit 0b2758f48f22 ("Require (reasonably) normal > mappings for MADV_DOFORK") containing my hands-down favourite call out of > all time. >=20 > Express the same thing using the predicates - only mm-backed mappings may > have their copy-on-fork behaviour changed, retaining the eternal exception > to all rules, hugetlb. >=20 > No functional change intended. >=20 > Acked-by: Zi Yan > Acked-by: David Hildenbrand (Arm) > Signed-off-by: Lorenzo Stoakes (ARM) Sashiko has reviewed this patch and found no issues. It looks great! --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261013-b4-mmap-pr= epare-vma-flag-sanify-v6-0-1aa3c9b139f9@kernel.org?part=3D33