From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta1.migadu.com (out-120.mta1.migadu.com [95.215.58.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1192C1CAA6C for ; Sun, 18 Oct 2026 07:59:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.120 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792310381; cv=none; b=U5NuNO9U+DcStN30mYf0W+vUQtFkC8QcxMTflUp17loPAFjoWYRO7/xRKG+KcoATwV/kDEGWwcnd5PVqMJkLcmO1fb88Z+nuXCqqzSS3YAN3yQCK5G1LNl/pdj4ymqLPKmpnMzqnp7Ct4Ml5PawGkJuSM5mUFXEDrO5RA0POlVk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1792310381; c=relaxed/simple; bh=lyELolJu2xi7BInGaBj0/nHK9JAkLFJ3iwidm/fclC4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=S2XnJBiz21Am8BC3FZlZ0ZrCKGZsE3pDEe9Ai6XqiRHkPnec6K6Q59hsVotWsYZFMutHngTzr+5YUD/FIXYo9L0s8YjCFMX5b8I7zEi3LKf8oPpMUvlYcP+5nNzkixYrhPixdLX7JAliR7wj91Clu1DM9HrVoR1dNya58nY8FDY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=lfrWoAoq; arc=none smtp.client-ip=95.215.58.120 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="lfrWoAoq" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=lyELolJu2xi7BInGaBj0/nHK9JAkLFJ3iwidm/fclC4=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1792310377; v=1; x=1792915177; b=lfrWoAoqPBnkUHg2TbGWDXZnc3sz1EwVdyHFT9QFlOOqd++K/YkMRCXa6Hy1w9702VnPO7F9 bs7chR5uCdrXv7hE5tlHCqjppDu8zNGXix1VyMDYs5Ax55vtWtz4JU6jg9T5WB2N7em8yVI5Ncj GEBYURkYJvRqug+9Gusqvq08= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 77426602997a8cfb; Sun, 18 Oct 2026 07:59:36 +0000 X-Mizu-Trace-ID: 77426602997a8cfb X-Migadu-Flow: FLOW_OUT From: Lance Yang To: david@kernel.org Cc: akpm@linux-foundation.org, liam@infradead.org, ljs@kernel.org, vbabka@kernel.org, jannh@google.com, pfalcato@suse.de, muchun.song@linux.dev, osalvador@suse.de, linmiaohe@huawei.com, nao.horiguchi@gmail.com, agl@us.ibm.com, mel@csn.ul.ie, riel@surriel.com, peterx@redhat.com, kas@kernel.org, rppt@kernel.org, josef@toxicpanda.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: Re: [PATCH 07/10] mm/hugetlb: tolerate uffd bits set without uffd for PROT_NONE PTEs Date: Sun, 18 Oct 2026 15:59:27 +0800 Message-ID: <20261018075927.2979-1-lance.yang@linux.dev> X-Mailer: git-send-email 2.49.0 In-Reply-To: <20261015-urgent_fixes-v1-7-42796911043b@kernel.org> References: <20261015-urgent_fixes-v1-7-42796911043b@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=UTF-8 Content-Transfer-Encoding: 8bit On Thu, Oct 15, 2026 at 06:07:13PM +0200, David Hildenbrand (Arm) wrote: >The whole uffd handling when a VMA is unregistered from UFFD is shaky: >there are still some scenarios where we might have stale uffd PTE bits >in VMAs no longer registered for UFFD, which confuses other code. > >Let's just tolerate that for now and simply clear the PTE bit. Add a >TODO to really clean up any uffd leftovers when unregistering a VMA from >userfaultfd. > >The handling is now more similar to what we have in handle_pte_fault(). > >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) >--- Reviewed-by: Lance Yang