From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=90.155.50.34 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794256253; b=mdt4awlZItaTf55Yr7AqnyQlNNYldQqb677rdX4CTHsVnH0Lsbh+j32YTlS7gWdU8jBY p0ofLByg+8sN+w66VBYQFGqwvvHjlcpdx72nfoqAq95ESmjEkhyzfe5Q5ryCqu5XlcMcx r7AS6eMwCJn98b+BFmSQx6wjCMP1S+5myEymKhXAtm2cPn1usFJ1vQXfHbTVfVy+rxBA8 akaDBVwXqius32Il9LekBTlt338B1Imwf6A6Hszjjz9KfM+E4y/hRD34GNkSwdrh7TJa9 1LSWFN35yMlCBDDL2U9sjwE+usXvcx4iLxzfaHlbmWDbsX+thisgHTj/u/HdcsazYrg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794256253; h=DMARC-Filter:DKIM-Signature:Received:Date:From:To:Cc:Subject: Message-ID:References:MIME-Version:Content-Type:Content-Disposition: In-Reply-To; bh=8fiDCQCRdhXgmLQB5RoXvNckgRlJaUgMVt4yvwE8wp0=; b=hqtn7ysDU3YO/SSVZU3s3Zlz8FsSy8JO47IAFAJRcdj+p4vWQkgsJFDvYPpbHjsjUQq7 34yzZ301XJUobpEYfLhpqsg+RHYZMtfrhk2tjnvzjbPEvcD5RG9FqRrh6JTqNZum5Kvi0 O1Wn+pi8Vf6xZlpFCV79L3pJHR6E54sJPl77IbXaVxUpE/arbRh/vWmwrWoFoHSV+Q6EA dKM50WKfsi887RuDHKeaArRmaPqWCFGcBxtY8ifCMf+0VLOCwcqQNCMQiZ/YDJGY7Uqx5 uL6RslQZOVmXtXeMJ4V1iVngta2Bj5e/SVkMJDVQBt0FCsieg9YYfB9ddAERw4QOXXg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=infradead.org; spf=pass smtp.mailfrom=infradead.org; dkim=pass header.d=infradead.org header.i=@infradead.org header.a=rsa-sha256 header.s=casper.20170209 header.b=o+ZHiSlL; arc=none smtp.remote-ip=90.155.50.34 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5A664606A31C; Mon, 9 Nov 2026 20:30:52 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 5A664606A31C Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=infradead.org header.i=@infradead.org header.a=rsa-sha256 header.s=casper.20170209 header.b=o+ZHiSlL DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=8fiDCQCRdhXgmLQB5RoXvNckgRlJaUgMVt4yvwE8wp0=; b=o+ZHiSlLjBJBn2ee3/lPBmRaSs VryBh9nDG8CuqdYgskBC0HfggwANkB3rxDS+VJs6NhztS84Tvg5pkagIvdKZZjuL9AN3gVZVL/yck wH5DnIFA8gxoTQdMEHgVLFJyphVxU/t3hRUF82o2h1zlB4AfNB8apqmUACY2FzocTTYdnCwfUAsGn TXfdtUC9XT6yHugH94idT1au2Wozd/Q7KscUnDZDAUvi3R4H4KzIrUB1eK6wetfnuQFbXwjl6GE91 ANuBzWrTdFrQJu2WqNOp0H5HnRSlWZxNJfmWJ3XD7zRm2/sYafNoJwumff8oKyhMJ32MxtX0r8a1F sZOjsevA==; Received: from willy by casper.infradead.org with local (Exim 4.100.1 #2 (Red Hat Linux)) id 1xQW0u-00000000jrk-0IQW; Mon, 09 Nov 2026 20:30:48 +0000 Date: Mon, 9 Nov 2026 20:30:47 +0000 From: Matthew Wilcox To: "Kiryl Shutsemau (Meta)" Cc: Andrew Morton , "David Hildenbrand (Arm)" , Pedro Falcato , Lorenzo Stoakes , "Liam R. Howlett" , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Hugh Dickins , Chris Mason , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@meta.com, Sashiko Subject: Re: [PATCH v2 1/2] mm/memory: recheck PG_uptodate after ->page_mkwrite() Message-ID: References: <20261109120403.82361-1-kas@kernel.org> <20261109120403.82361-2-kas@kernel.org> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261109120403.82361-2-kas@kernel.org> On Mon, Nov 09, 2026 at 12:04:01PM +0000, Kiryl Shutsemau (Meta) wrote: > do_shared_fault() unlocks the folio around ->page_mkwrite(). Writeback > can lock it in that window, fail, and clear PG_uptodate with the folio > left in the page cache. ecryptfs_writepages() does this when encryption > fails. filemap_page_mkwrite() relocks the folio and checks only > ->mapping, so the fault maps a folio that is not uptodate: Filesystems that do this are buggy. They shuld be fixed, not worked around like this.