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 AFC8D606A31A for ; Fri, 30 Oct 2026 03:41:29 +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=rvK89E9A; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=n5wUI5FV 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=QEX9vlMNf/S5h2VpPXqypsfpqZC9bn2dXekRVGh41+I=; b=rvK89E9AOcdiPaGt6FRVUZugMd l6DlnPzD43+1OgyS4b4HvJWb5l7P+Dl3hrWVRr6dPyyD0hnoTeC/3iS3M8Y+bjCDeoOcV2IRW+ioD G5ABdS3u8HeGpjcsQdw/4G/atReDi4E7wqb4FGdx8KC40emII/epJLV50za9z3J65I2qPMwsHYIq3 2ir9iidRNsn1c0ACnCJckxvxokzUKEJPwq8iZms7Zi726gFRSUDmIQuPH0L4O4AiMAnKqOUQ4lW5G 8BfIE8R3XC64FfcQjMW+Zpe9Myg4Ui5alk3xHtskGQO108AQyQl8gU9RxrpP72E5enw9BVyuC3Qqs Bd/yqkRQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xMdUf-0000000AkT6-1gUt; Fri, 30 Oct 2026 03:41:29 +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 1xMdUd-0000000AkSY-3pxk for kexec@lists.infradead.org; Fri, 30 Oct 2026 03:41:28 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 5CF4B600E4; Fri, 30 Oct 2026 03:41:27 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7D48C1F0093A; Fri, 30 Oct 2026 03:41:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793331687; bh=QEX9vlMNf/S5h2VpPXqypsfpqZC9bn2dXekRVGh41+I=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=n5wUI5FV0LBZ9l0/JQtUOJ/CNnlfwfy/QEwMm0M2jl9OSdaGfy0pF/kptqwzlkoyt AXFCyUHVeh59TIcW4u/zAnMSdZpgKp1CB8ed1AAlLelNjrs9i78aBoJeMNL9rMhrhx 3UXJlXwiN6ImjLEdOBiKqBUBPjqRsOVW+ZxpZBkJB9iFXD6D1gkP4z0G0q9ndF2IXN 9cnI6jkO8wSIprccwvAJ4yZDiizUY5APIatreyzN5r1ClZxBg+32Tr0K9WBUUXJP3Q tX1HSijn84bmfqHIt+8AvPFKCht1oDNAMCyIRL0Ii8HGWKa3qkobhFjnboMcd1hYyf 8ELxsaj8UqP2w== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v2 23/47] 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: <20261029-fixes_core-v2-23-a64ce7f83abb@kernel.org> References: <20261029-fixes_core-v2-0-a64ce7f83abb@kernel.org> <20261029-fixes_core-v2-23-a64ce7f83abb@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Fri, 30 Oct 2026 03:41:24 +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=-10.9 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 > Reviewed-by: Mike Rapoport (Microsoft) > Reviewed-by: Lorenzo Stoakes (ARM) > Reviewed-by: Suren Baghdasaryan > 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/20261029-fixes_core= -v2-0-a64ce7f83abb@kernel.org?part=3D23