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 DE5F2606A31B for ; Tue, 27 Oct 2026 00:13:18 +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=SJmKr+xP; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=e6JOiR4P 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=DiTYHDYloiDXDB3BMzDj0RO62BC6UszYQ9AKb+ZwFyk=; b=SJmKr+xPJLBkcq5tfMgT8gZ7JC MCCr8ZkKubsIsi+2A+oVlVflJ4gPOik374Khcd5FiDWzOsXpJQeNfK9r6PAV2FlbyFf2xCN/tnPhH 3zhLugPWSSYb1+FqB9829mk33ZMePwip2KoDwnB5gE0khdYCcSHw5anzCWmGs6iefVZRyRtmacdvw K4Q+xEdp6fHSUI7jggoE/ktKGVQqpLg0rvJBZM5RNeqj18lPoLyOfjDAzpgnmFt3RXh8qofVYBRe3 2k2LeB1JT2NLCEeYW/aMy4NxaNtRZXeWiSXatLOERDqpPqQ6mBLj101KuW+xpk5dzaKM6NOc+eu36 RuWcztfQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xLUoY-00000003VTO-2fkQ; Tue, 27 Oct 2026 00:13:18 +0000 Received: from tor.source.kernel.org ([172.105.4.254]) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xLUoX-00000003VSd-2lRA for kexec@lists.infradead.org; Tue, 27 Oct 2026 00:13:17 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 1C91060200; Tue, 27 Oct 2026 00:13:17 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D76891F01825; Tue, 27 Oct 2026 00:13:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793059996; bh=DiTYHDYloiDXDB3BMzDj0RO62BC6UszYQ9AKb+ZwFyk=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=e6JOiR4Pm/UdFOR+0tFZ9ABK9p82LHi26rfAyqqBv5Wuj3sdAOpWgzajrDFg02E3o brfx46Z0M3JtdB3CgkEtUH2D9TXH94whTLJ4GjC4J1zR3vViBkBY7WrtHRer7l8g1W oPUoTUprGI/6H8tKTHMBkGyzY20tS3SdBrpcsrE0NI4xWTq8gCHHw64t3RNEjH2PFC xph/9fCRk1snFC/OvPsArEAiTR3cNinO1EGCbYNk3u+8Ob7mKbxI8fnynUhg3e9WC0 ciN5IXgmNIlDJ9CwQJGdoe6J8hDkv/Ilb887L9OIhB1Z+2Tz1xSF3cKeNOsmVzDB+e ZgKTKfO0qlJiA== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH 23/46] mm/userfaultfd: write-lock the VMA before waking waiters when unregistering 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, "Josef Bacik" In-Reply-To: <20261027-fixes_core-v1-23-6f74bec9a5bb@kernel.org> References: <20261027-fixes_core-v1-0-6f74bec9a5bb@kernel.org> <20261027-fixes_core-v1-23-6f74bec9a5bb@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 27 Oct 2026 00:13:13 +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: > userfaultfd_unregister() wakes pending missing faults before clearing the > VMA's userfaultfd registration. With per-VMA fault locking, holding > mmap_lock for write does not prevent another fault from queuing after > the wakeup but before userfaultfd_clear_vma() write-locks the VMA. That > waiter can then remain asleep indefinitely. >=20 > Call vma_start_write() before waking waiters. Existing fault handlers > queue themselves before dropping the VMA read lock, and new readers are > excluded until mmap_write_unlock(). >=20 > Fixes: 29a22b9e08d7 ("mm: handle userfaults under VMA lock") > Cc: stable@vger.kernel.org > Reported-by: Josef Bacik > 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=3D23