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 5055E606A31A for ; Fri, 30 Oct 2026 03:40:21 +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=g10SlnLR; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=ajfNbetm 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=5v0UtZ5ZpgXYzdCDzW8ShE6wLydrETG0DJU+ieCebmw=; b=g10SlnLRNRJFB5wZ1iJB/yLNZ1 Ns3/DYMMHtu+jWjdLvRP1pJj26mTM5mWI+NJkl8Nwt1Nd2qHgTHjgbGKKgZIMihVybp+4T3RUn577 qMhjVpbtgr80fefCwRCD5ppIpPGGFv43AgGPCnfGr9wXsfYPyw6cBY68b7NHSf1/vCQ7guGytROsx EVR666XCw9iNpXnX4b6zCWr8/DP9ElbFb7XnF0KBuJSpcJmfBKevUH+veLlYrNepLBnsPlettxzhN IXIc6wZv199hBYAIlYXvYS8lYrXtE42ijfSlO6PspRHm72z0JURxrY6RgVitoIRobKJLaF9tBwoku xNtJTleA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xMdTY-0000000Ajgf-42zW; Fri, 30 Oct 2026 03:40:20 +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 1xMdTX-0000000AjgF-2Yrz for kexec@lists.infradead.org; Fri, 30 Oct 2026 03:40:19 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 1F76C600C8; Fri, 30 Oct 2026 03:40:18 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4930C1F000C1; Fri, 30 Oct 2026 03:40:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793331617; bh=5v0UtZ5ZpgXYzdCDzW8ShE6wLydrETG0DJU+ieCebmw=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=ajfNbetmsY9U808TXgcqqgcvjds805VvFy36NFREcxwhXQOAcCeWjg41Bg/OZkwBD ER5qAaHBAyklYhdfnVPISigmgB1yv7aVvyMH667/0jxdGvv+qCqRXy1h4SzyXx9ZUV Qv1MsloCVdk6WMZPLH/H2K3TFKK/EMd4YKCk3wi5LqBgsUACexSxwhwA9VdB+hsov5 jRtCMvXqPZC7esf4TlPXDxupmwnuyn6B9si5Mxy52cuCV+VwC/uHauWA3t12U02/7q N+/bNaukJ6Snox2PB/c7vMUf34iEYRfxbxFuwNkcTnrCXhjlxUMY/Cf7ajpu3H6QHv /Z0ZlvxktlDeg== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH v2 02/47] fork: take mmap_lock before copying mm_struct 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-v2-2-a64ce7f83abb@kernel.org> References: <20261029-fixes_core-v2-0-a64ce7f83abb@kernel.org> <20261029-fixes_core-v2-2-a64ce7f83abb@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Fri, 30 Oct 2026 03:40:14 +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: > dup_mm() copies the parent's mm_struct before dup_mmap() takes the > mmap_lock. A concurrent brk() can leave the child with a stale mm->brk > and newer heap mappings, causing later brk() requests to fail. >=20 > Other operations (e.g., PR_SET_MM) on the parent's mm_struct can similarly > cause inconsistencies. >=20 > As a simple and robust fix, grab the parent's mmap_lock earlier. This > way we don't need to update individual mm fields in dup_mmap() and > keep missing ones. Stop updating the 4 existing members (total_vm, data_v= m, > exec_vm, stack_vm), as that is now no longer required. >=20 > Keep releasing the parent's mmap_lock in dup_mmap(), before > userfaultfd completion, to avoid moving the userfaultfd handling into the > caller. This should get cleaned up later. >=20 > Move uprobe_start_dup_mmap() to preserve the lock ordering. >=20 > Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") > Cc: stable@vger.kernel.org > Reported-by: Josef Bacik > Reviewed-by: Lorenzo Stoakes (ARM) > Reviewed-by: Rik van Riel > Reviewed-by: Vlastimil Babka (SUSE) > Reviewed-by: Barry Song > Reviewed-by: Pedro Falcato > Reviewed-by: Harry Yoo (Meta) > Reviewed-by: Kiryl Shutsemau (Meta) > 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=3D2