From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.subspace.kernel.org (Postfix) with ESMTP id C6C63606A321 for ; Fri, 30 Oct 2026 00:34:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=DduHRuPY Received: by kanga.kvack.org (Postfix) id 931336B00EF; Thu, 29 Oct 2026 20:34:46 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8E31C6B05B1; Thu, 29 Oct 2026 20:34:46 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7D3E46B05B2; Thu, 29 Oct 2026 20:34:46 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0016.hostedemail.com [216.40.44.16]) by kanga.kvack.org (Postfix) with ESMTP id 58CD46B00EF for ; Thu, 29 Oct 2026 20:34:46 -0400 (EDT) Received: from smtpin08.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay06.hostedemail.com (Postfix) with ESMTP id E378BA81D9 for ; Fri, 30 Oct 2026 00:34:45 +0000 (UTC) X-FDA: 85377422130.08.97F96B0 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf11.hostedemail.com (Postfix) with ESMTP id 45A3440003 for ; Fri, 30 Oct 2026 00:34:44 +0000 (UTC) Authentication-Results: imf11.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=DduHRuPY; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf11.hostedemail.com: domain of sj@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=sj@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1793320484; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=J6qvhedKX/gt9L39bpVgRBd7A0g16i9D1HZNiTvqkfw=; b=oisN1mMpGHIoFKWfOwt+wNKsJ79f21d4fgHkne/YUoOuZ0F6dkX2+R2eFVjWynwWB1Q7/i u9b9y1yZB7r2uFID8Hs3p4m8rtwLmFb+W2NEDnhm5M4iYDAPEGKXISAt8mowt4Myy8IzZ3 70zLWlB3VL9x7JYgSaTu08nha3dRfzQ= ARC-Authentication-Results: i=1; imf11.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=DduHRuPY; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf11.hostedemail.com: domain of sj@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=sj@kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1793320484; b=oPhG5TzoWyRF/KVW2+FfEoh0VLYie2pKgLgHDSb27jITng2udTwV0LCf/OO9XUYrp19SXe z2yhC3GvG8S3jryxiSjTjuOTfQF6eFT7bBuzyZ0RVQlfJQdJk4wlgV693x3FbqCdynqyK2 c1hmZt43myLDe3az+lCsx5FwFqoIKKo= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 3F6AC438A6; Fri, 30 Oct 2026 00:34:43 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 03BF11F000C1; Fri, 30 Oct 2026 00:34:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793320483; bh=J6qvhedKX/gt9L39bpVgRBd7A0g16i9D1HZNiTvqkfw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=DduHRuPYmFLQVXIsNcNjApO97/T8X2q8UAfCyYP1FbDA55gYCiFqIxgKlBRMzDPCT Eqs2Hx8NW5JNHHOwoaWAREmZ9P3g0DpqSD6ZIAALIBan8uNdEC7bloNBM6ojVGEYVk FENFOG2Gdb/Pe7A0j+ozRR73EUaDH16qGjtXlvUo9kWAgkt1QHi+VdagnEw8C8T74j Yr8bysC4D0OxTeYJFfW5QuO9Da+Ehdf3XvdtWlh8G5C0H/tFFCwNzQnltS9dLOayxj OH44Anbtpxbx/w1SEQjMZhJc6+ynBnLLft0fXjVDgMDV3v73CICkPnVUjb7wRDMMx3 S8ms98yTtaxtw== From: SJ Park To: "David Hildenbrand (Arm)" Cc: SJ Park , 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 , "Matthew Wilcox (Oracle)" , 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 , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-arch@vger.kernel.org, linux-cxl@vger.kernel.org, stable@vger.kernel.org, Josef Bacik Subject: Re: [PATCH v2 02/47] fork: take mmap_lock before copying mm_struct Date: Thu, 29 Oct 2026 17:34:33 -0700 Message-ID: <20261030003434.154864-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20261029-fixes_core-v2-2-a64ce7f83abb@kernel.org> References: X-Archived-By: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 45A3440003 X-Stat-Signature: uhc893w9c936i41p9gewbrqawogx756r X-Rspamd-Server: rspam04 X-Spam-Status: No, score=-13.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_PASS,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=4.0.1 X-Rspam-User: X-HE-Tag: 1793320484-787589 X-HE-Meta: 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 ecaJeJOC cZRdxNXrL1gMvcj/xZYlK8wlKlLB5pqjD08twNSvg5BKgkA0n6iPVMDG6Gb75ObPmCisWoTa8enRzZn2dQVVGSAqsstnS4kkOc+asPFJt15M0XclHGIBF1LBd3z5om5+lPAu5Jyj4U4BRhVhqaoJVLXeX63aHY5+pEgMRwn3juV9XeQLAdPFE8/OYAYPhKydsySS8BP5fNXv3PiE1nfgtXB9UOsBcpjPYuRhQCCrl6ZY11cpdLMhvAKTz7b/cogDMA6QaIt2/GsgZuvwGdaPp5vZ6TL9ZCEiwq2FxiYEvai6NYJXDl+iQ4sP4axR7Ht3DQBYdn0eBJ8RA5PfY2rD8e5FcGS2uxgAGCKlD7+UwCiHfwaoGn+C2CmVTX5867zpXJEbHIsqN/plt6eHnt0D9UN3ZeAGRMqDzzqR6APd0l7+2Spshz2VY1/OTNq+1HnD6vngQOPRKGRsSrWyAXfcSXoLN+oejj2vn1gOE Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On Thu, 29 Oct 2026 21:32:57 +0100 "David Hildenbrand (Arm)" wrote: > 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. > > Other operations (e.g., PR_SET_MM) on the parent's mm_struct can similarly > cause inconsistencies. > > 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_vm, > exec_vm, stack_vm), as that is now no longer required. > > 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. > > Move uprobe_start_dup_mmap() to preserve the lock ordering. Looks good and makes sense to me. > > 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) Reviewed-by: SJ Park Thanks, SJ [...]