From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 645D8606A31A for ; Tue, 27 Oct 2026 00:13:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=lKeU7871; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=U70lx+73 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Reply-To:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:Date: Content-Transfer-Encoding:Content-Type:References:In-Reply-To:Cc:To:Subject: From:Message-ID:MIME-Version:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Unsubscribe-Post:List-Owner; bh=VTvU6qW9g7JLlCdqmBcDVKZfOal5ZUhUhwQCM6u7o48=; b=lKeU7871ky0Ze7BsxgeGmof0s3 SUxFVTTvkRxBSE19BpY8sqE3/rr+GqhfnrPNjA6Id7jUt3YDpwep00xpfkWCQGRe2CvGaBRSKaGRF yNgVlkFeLRxSOonYxvehZvWHXZNSkISqwUnMfEYlPAnzXfjSpWsyXIOh4zzhZ56hS6+mQiNq4no8R hFV9/OGzafiafeYrYOzoL1T7XJG+nSME/1Tq+WX/0ABC5w/Xwe5gJEdV941KSbui2FUm4F4CZF2TU q8fB4dqvsm5aVrDarlg5c7HT7af6jim/YLd6IqDtb7FnS1qzdOYKY6hIPAvm7goEKDNnCPk2o5Msh mxDtv1TQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xLUof-00000003VYG-0DzS; Tue, 27 Oct 2026 00:13:25 +0000 Received: from tor.source.kernel.org ([2600:3c04:e001:324:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xLUoe-00000003VXi-1FFV for kexec@lists.infradead.org; Tue, 27 Oct 2026 00:13:24 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id B8643600DA; Tue, 27 Oct 2026 00:13:23 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BEF6E1F01825; Tue, 27 Oct 2026 00:13:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793060003; bh=VTvU6qW9g7JLlCdqmBcDVKZfOal5ZUhUhwQCM6u7o48=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=U70lx+73oMWUbz1Zk/6binrbPvLhUei/UTb0qakokdSgC9LwVL+lVXKAQ9ZCghgjm oRSlXtPzkfDPLshMIEfalsGadMa4V8wjV9MY00sUcACbDHqNtMy5PLe744M/essBXe JjBYh6tI8Aeyw95VUpJQ1NXW9kSdPWuIBwwjXd5GeKEJ8WYpbErXuNUskRVsiMz2Ow CXoxdT3lDIFJ53rlKOgQJ4TTycDwum0jJN0neIHcgbEUzIQKbKKugP4PQ5bxB6Z7lT yxqgOfOAFgWSFhCfeETWLBk/Jl7zDQxM62b+oYqcdrQfS9+2c02lveex6QT206DYF/ OsINmKxMRqJEQ== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH 25/46] mm/userfaultfd: wake waiters when registration modes are removed To: =?utf-8?b?RGF2aWQgSGlsZGVuYnJhbmQgKEFybSk=?= , "Andrew Morton" , "Johannes Weiner" , "Michal Hocko" , "Qi Zheng" , "Shakeel Butt" , "Lorenzo Stoakes" , "Kairui Song" , "Barry Song" , "Axel Rasmussen" , "Yuanchu Xie" , "Wei Xu" , "Baoquan He" , "Baolin Wang" , "Liam R. Howlett" , "Vlastimil Babka" , "Mike Rapoport" , "Suren Baghdasaryan" , "Michal Hocko" , "Kees Cook" , "Peter Zijlstra" , "Jann Horn" , "Pedro Falcato" , "Hugh Dickins" , "Pasha Tatashin" , "Pratyush Yadav" , =?utf-8?b?TWF0dGhldyBXaWxjb3ggKE9yYWNsZSk=?= , "Jan Kara" , "Zi Yan" , "Lance Yang" , "Rik van Riel" , "Harry Yoo" , "Alistair Popple" , "Nico Pache" , "Ryan Roberts" , "Dev Jain" , "Usama Arif" , "Kiryl Shutsemau" , "Matthew Brost" , "John Hubbard" , "Peter Xu" , "Will Deacon" , "Aneesh Kumar K.V" , "Nick Piggin" , "Oscar Salvador" , "Minchan Kim" , "Muchun Song" , "Xu Xin" , "Chengming Zhou" , "Chris Li" , "Kemeng Shi" , "Nhat Pham" , "Youngjun Park" , "Gregory Price" , "Joshua Hahn" , "Rakie Kim" , "Ying Huang" , "Jason Gunthorpe" Cc: kexec@lists.infradead.org In-Reply-To: <20261027-fixes_core-v1-25-6f74bec9a5bb@kernel.org> References: <20261027-fixes_core-v1-0-6f74bec9a5bb@kernel.org> <20261027-fixes_core-v1-25-6f74bec9a5bb@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 27 Oct 2026 00:13:20 +0000 X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: sashiko-reviews@lists.linux.dev Sender: "kexec" X-Spam-Status: No, score=-11.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 X-Archived-By: > UFFDIO_REGISTER can replace MISSING or MINOR tracking without waking > faults that are already queued. For example, switching an anonymous > range from MISSING to WP leaves a missing-fault waiter asleep until > userspace explicitly wakes it. >=20 > When a registration change removes a UFFD mode, wake waiters in the > affected interval after updating the VMA. The VMA is write-locked at > this point, so no new faults can queue under the old modes and woken > threads cannot retry until mmap_write_unlock(). Waiters for retained > modes in the same interval may also wake and refault. >=20 > The hang reproduces for MISSING-to-WP and MINOR-to-MISSING transitions, > with both read and unread fault events. >=20 > Fixes: 63b2d4174c4a ("userfaultfd: wp: add the writeprotect API to userfa= ultfd ioctl") > Cc: stable@vger.kernel.org > Signed-off-by: David Hildenbrand (Arm) Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261027-fixes_core= -v1-0-6f74bec9a5bb@kernel.org?part=3D25