From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D29BFCCD1BF for ; Tue, 28 Oct 2025 06:40:30 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 18DD880123; Tue, 28 Oct 2025 02:40:30 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 13F25800E4; Tue, 28 Oct 2025 02:40:30 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0545680123; Tue, 28 Oct 2025 02:40:29 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id E3E19800E4 for ; Tue, 28 Oct 2025 02:40:29 -0400 (EDT) Received: from smtpin07.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay10.hostedemail.com (Postfix) with ESMTP id 74946C03DE for ; Tue, 28 Oct 2025 06:40:29 +0000 (UTC) X-FDA: 84046574178.07.8333B25 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf22.hostedemail.com (Postfix) with ESMTP id A5443C0003 for ; Tue, 28 Oct 2025 06:40:27 +0000 (UTC) Authentication-Results: imf22.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf22.hostedemail.com: domain of dev.jain@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=dev.jain@arm.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1761633628; a=rsa-sha256; cv=none; b=0gbrUDBLAJAvNdoWbITaBx+7k68+zzcHZf+ZRVl4MNjZrglZOB3Exq2q0LB6AhG1rHbj8B Wj2GagSGiZgWYM0gfm0xnNu/tpn2RMzig7ZNBDKURQOUlvGok8MD8ttTzSp7Ib0RyPLjNb vZFg3VPn/9qeArEurqqu1bpG3ARepHs= ARC-Authentication-Results: i=1; imf22.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf22.hostedemail.com: domain of dev.jain@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=dev.jain@arm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1761633628; 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:references; bh=Gib7w9/Uv8x6admdPu841V7rBSvfwIccTBUvFietYn4=; b=e/+nmXmKpeXHSWBrl6Cc2CXg0IscACxAYYfnfGZX3MdlZdczyGa8ZTVU4nYzKqEbNwQpRi WrSm7e+a5nPXrvSACsZ/wpcLjj6gz3nzPiohWhUFQEqhviQG7QA96Wig6rmXxwwlFdWk7Y 94g+/Kt0n+K8FNyMRn7lDPLBKPoKNkY= Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id AE26D168F; Mon, 27 Oct 2025 23:40:18 -0700 (PDT) Received: from Mac.noida.arm.com (Mac.noida.arm.com [10.166.150.28]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 4C06A3F63F; Mon, 27 Oct 2025 23:40:22 -0700 (PDT) From: Dev Jain To: linux-kernel@vger.kernel.org Cc: Dev Jain , stable@vger.kernel.org, David Hildenbrand , Andrew Morton , "Liam R. Howlett" , Lorenzo Stoakes , Vlastimil Babka , Jann Horn , Pedro Falcato , Barry Song , linux-mm@kvack.org (open list:MEMORY MAPPING) Subject: [PATCH] mm/mremap: Honour writable bit in mremap pte batching Date: Tue, 28 Oct 2025 12:09:52 +0530 Message-Id: <20251028063952.90313-1-dev.jain@arm.com> X-Mailer: git-send-email 2.39.5 (Apple Git-154) MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: A5443C0003 X-Stat-Signature: d47rq3zbhywdizir3oj8ppdjif9ng7pb X-HE-Tag: 1761633627-380867 X-HE-Meta: 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 EBxQC0cP JVRpUXtaNAd8HmU1G4lR5XdF3No/c5+gQ2yVh609o8XkgHA8snv3nnxGFIpYizDIcGxw7BeGP6ZSE0WYT/L38SwrQ+kbNjod2faJiKnQBe3ag1fuHoeiP28iqFcimAUVchKlzyfQuNYPofl8vAyD3ezqOG3kWh/SslLe2SemSWORzbJO4LCyZV5mo7pBAOOIDN7K9ad+/C4ENOpA43onNCLANgZZEumW82omdygZTSbGNRAU= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Currently mremap folio pte batch ignores the writable bit during figuring out a set of similar ptes mapping the same folio. Suppose that the first pte of the batch is writable while the others are not - set_ptes will end up setting the writable bit on the other ptes, which is a violation of mremap semantics. Therefore, use FPB_RESPECT_WRITE to check the writable bit while determining the pte batch. Cc: stable@vger.kernel.org #6.17 Fixes: f822a9a81a31 ("mm: optimize mremap() by PTE batching") Reported-by: David Hildenbrand Debugged-by: David Hildenbrand Signed-off-by: Dev Jain --- mm-selftests pass. Based on mm-new. Need David H. to confirm whether the repro passes. mm/mremap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/mremap.c b/mm/mremap.c index a7f531c17b79..8ad06cf50783 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -187,7 +187,7 @@ static int mremap_folio_pte_batch(struct vm_area_struct *vma, unsigned long addr if (!folio || !folio_test_large(folio)) return 1; - return folio_pte_batch(folio, ptep, pte, max_nr); + return folio_pte_batch_flags(folio, NULL, ptep, &pte, max_nr, FPB_RESPECT_WRITE); } static int move_ptes(struct pagetable_move_control *pmc, -- 2.30.2