From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 6C9BA33557E; Wed, 19 Nov 2025 09:06:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763543212; cv=none; b=sGcyaQ9DsFXIopTsVtcVumAJjduaj7UwGyAtLscozZcVrm+DKbVfnUbDCsJndnCcxnwS3jIX8iRVnWc8wydCwN7ubcCXq3R2JhriptM0CR/jvEWXxGfYZ4Y0gSegH+bA9F/v0E1IUlWGEWaKVtC2q1W/AJpweeRmY/PRGN4HYCI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1763543212; c=relaxed/simple; bh=9VkQQVp1GUJZvklIUdL6yF9pgR7bsQTx3z4kO9z5dMw=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=gkZhfmJS5BzGr6ln5WbU+ofXXRD6NBfaXwOc7I5ERbjyvNOZ0TGrvzY+ifxts/HWblOegGwV46qaUHZtZzhPtizra7c4RLz1qox3odaq61zG3F9P932K+JPbxna64SFdQeOlLObpb/e48hbJ8yiMdfmdAIp6qXHw7Bn56gYWDp4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=OtVFxRZI; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="OtVFxRZI" Received: by smtp.kernel.org (Postfix) with ESMTPSA id DB818C19422; Wed, 19 Nov 2025 09:06:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1763543209; bh=9VkQQVp1GUJZvklIUdL6yF9pgR7bsQTx3z4kO9z5dMw=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=OtVFxRZIeWCKgm/wX8Mh4xSUKUsDu7TC61ZcbwB7p755P/p8D1UbOzn887vZKWsiT LT8Hkl3H3DdI8TLAeKktrX3yWPQQeQzoD5az9ce9h9AJFO474lVbcQaSZN4cdtnOd8 qMzgerN86Kq5LjGLmF8Xvx0kt31CQR/SNyrzETsVCfIlrjxK/jwXc0n9+UEq8FW+87 frsGoVcUKPI4zE7zMA2vs5hS+GVhuQnNfj1tCMielj1RrXvfjcbkBaPmp99gNYG86X g8w2OOyBsEud9UYPSoka4/54CHPtP2JqM1W+W7dvk4+P26CuXNiNahahWDLbiZIptV UKv7ewASeZOgA== Message-ID: <9b18ee75-bf06-46d7-96f3-395cb159217b@kernel.org> Date: Wed, 19 Nov 2025 10:06:39 +0100 Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 2/9] mm: add atomic VMA flags and set VM_MAYBE_GUARD as such To: Lorenzo Stoakes , Andrew Morton Cc: Jonathan Corbet , "Liam R . Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Steven Rostedt , Masami Hiramatsu , Mathieu Desnoyers , Jann Horn , Pedro Falcato , Zi Yan , Baolin Wang , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Andrei Vagin References: <97e57abed09f2663077ed7a36fb8206e243171a9.1763460113.git.lorenzo.stoakes@oracle.com> From: "David Hildenbrand (Red Hat)" Content-Language: en-US In-Reply-To: <97e57abed09f2663077ed7a36fb8206e243171a9.1763460113.git.lorenzo.stoakes@oracle.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 18.11.25 11:17, Lorenzo Stoakes wrote: > This patch adds the ability to atomically set VMA flags with only the mmap > read/VMA read lock held. > > As this could be hugely problematic for VMA flags in general given that > all other accesses are non-atomic and serialised by the mmap/VMA locks, we > implement this with a strict allow-list - that is, only designated flags > are allowed to do this. > > We make VM_MAYBE_GUARD one of these flags. > > Signed-off-by: Lorenzo Stoakes > Reviewed-by: Pedro Falcato > Reviewed-by: Vlastimil Babka > --- IIUC all other flag modifications need a write lock, so this should just work. Acked-by: David Hildenbrand (Red Hat) -- Cheers David