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 A9A72606A31A for ; Mon, 26 Oct 2026 23:22:40 +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=PVvbRksS Received: by kanga.kvack.org (Postfix) id C8E596B05CC; Mon, 26 Oct 2026 19:22:39 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C66246B05CD; Mon, 26 Oct 2026 19:22:39 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B7D736B05CE; Mon, 26 Oct 2026 19:22:39 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 963BB6B05CC for ; Mon, 26 Oct 2026 19:22:39 -0400 (EDT) Received: from smtpin04.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 142531208CC for ; Mon, 26 Oct 2026 23:22:39 +0000 (UTC) X-FDA: 85366354038.04.CFB3B96 Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by imf25.hostedemail.com (Postfix) with ESMTP id 32598A0003 for ; Mon, 26 Oct 2026 23:22:37 +0000 (UTC) Authentication-Results: imf25.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=PVvbRksS; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf25.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1793056957; 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-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=9PONecBNGwAC37JtDon9HRvZi6sk21qH9zGaaJ3qYwM=; b=QiXQGF4KIOvCgmZ51bWBhvPIki9+79cUynZaXaouQbZacv1LBD0h5fFzYjoOlc+Cs2WLti G5jdcqN3aqTymwy+r4iHyQ0pEwk9Vaelp8/Kuo4HLLhPhQUaFWEzIwyJZnvpmFOgum9iOr efFrbTKhkf5ooql3LfQyz5KNUDfuEGg= ARC-Authentication-Results: i=1; imf25.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=PVvbRksS; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf25.hostedemail.com: domain of david@kernel.org designates 172.234.252.31 as permitted sender) smtp.mailfrom=david@kernel.org ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1793056957; b=Uy8hgn7enfUIcmu7PVUEJyd/yvzZnDx9xZIaofEARsAi0ODf1/SmnVqUgGYjQGOG0k9qqu mJEy0LSYPjbqntS2vWXDrn8OapQoUzRHtqQuMdnqxp8MhGHtR89EUX64Ad2y5U/nc0deDZ /5yDMxxTwLq467M9UDnyPdZaUkc7lDI= Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 7AACC4017C; Mon, 26 Oct 2026 23:22:36 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 33E7D1F01825; Mon, 26 Oct 2026 23:22:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793056956; bh=9PONecBNGwAC37JtDon9HRvZi6sk21qH9zGaaJ3qYwM=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=PVvbRksSFwPLqVK97JfuGRK/yyQ7vgKqfwNLBuwg7tRyER/6D481w8uhIlExbvJlF 3Bu3BiC6oN4wuYX83Y+otwZqJERUGRe1XFi0KZ7UsLHZ/O4mJV3ZcTn/vc9WZT9EJX wPLTosWMrpja6FYcetEEULvCUUTsRwH1Wx4GCZRVT5tvL3HyQE+itWahkkZ0Dz60Ct XlR6V2Yu3twGvjCbCxFmeWQT5axPeMCrXg6qf9ZLt0Dkzq7EMrgWGUq4VcoD45xmNI 0JiJEmKhSJUPzB+HtPGHZQbcS0lXuOgWw7vLR2o9H5MUKaVvozkgATVGIROQa8biF8 hMVaFTFvhIV7Q== From: "David Hildenbrand (Arm)" Date: Tue, 27 Oct 2026 00:17:35 +0100 Subject: [PATCH 15/46] mm/khugepaged: always recheck the pmd in try_collapse_pte_mapped_thp() X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261027-fixes_core-v1-15-6f74bec9a5bb@kernel.org> References: <20261027-fixes_core-v1-0-6f74bec9a5bb@kernel.org> In-Reply-To: <20261027-fixes_core-v1-0-6f74bec9a5bb@kernel.org> To: 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 , "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 Cc: 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, Josef Bacik , stable@vger.kernel.org, "David Hildenbrand (Arm)" X-Mailer: b4 0.16.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=1502; i=david@kernel.org; h=from:subject:message-id; bh=tUVUPC0JtoDS0vcvc31VLhuGDhArP2SMJJKTyHtlpxc=; b=owGbwMvMwCF2/OVpCdfQ3ZWMp9WSGLLu359SPM9j88bSt686WqQe8L9xbvg+r1Tw8tRHcz37n s7RmJFY1FHKwiDGwSArpsgSFHzf4OXLdbXVbnzMMHNYmUCGMHBxCsBE5jcx/BU29ki5fl+GO4jN wXS6x7vf0VKJzI6z82R5Fk6a9kRS25nhv2NW248SjrK9fx+kGgX4OdfM0y+eYzZ9l+uy4BN7Is4 9ZAAA X-Developer-Key: i=david@kernel.org; a=openpgp; fpr=1BD9CAAD735C4C3A460DFCCA4DDE10F700FF835A X-Rspamd-Queue-Id: 32598A0003 X-Stat-Signature: bt17fkmpszemz5idxe658rm1r8unk41f X-Rspamd-Server: rspam04 X-Spam-Status: No, score=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=4.0.1 X-Rspam-User: X-HE-Tag: 1793056957-615487 X-HE-Meta: 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 /Z0JqxUh ELoqdpBmbDZvL0AvAEEPbYcsfNvbo88EM/b9trplDe9zUNC1hplDpR35SwdP/63cjYzm5cZS2O2ljaK5Jm2X2LWxTg5p+OslOHjpGhOaVHQPh5h0zzqAp09HWWdGetH2MLsm0l8FONIyCzZyB40QuvUWObr4RFssvJaepRGIKpNrhLBtVCZESvNjlE/GkxGIvKqB0rIYbKrJvZJDwX3XxX81m2XAZYo3mHz+RZVERPcUN7zuslpLpzsh0Zj3pHj3TQGkfTFQvFmR5Cuz1m8SOMnDrcVp+GahzqOfbklkpbDVmf2zXyIQw2/JiSYURu2u//JibS/vPSY2MhJnBzew/EAAY4cyD9HQ4a5k6T63NSQhM0aztQPrB9G5mw/FA9rjhjF61XSqiqKWeg015DUB04p6g9jw2rH24iGYIh0qJ1yFL/uw= 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 From: Josef Bacik try_collapse_pte_mapped_thp() drops the PTE lock after it has cleared the page table, and takes the PMD lock and the PTE lock to remove it. In between, MADV_DONTNEED with CONFIG_PT_RECLAIM can reclaim the page table. The pmd_same() check is supposed to handle this, but it is only done with CONFIG_SPLIT_PTE_PTLOCKS. Fix it by performing the check unconditionally. Fix generated by an LLM and sent by Josef Bacik in private. Fixes: 6375e95f381e ("mm: pgtable: reclaim empty PTE page in madvise(MADV_DONTNEED)") Cc: stable@vger.kernel.org Signed-off-by: Josef Bacik [ david: adjust description ] Signed-off-by: David Hildenbrand (Arm) --- mm/khugepaged.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 4b71d010b2aff..f53c50507c83d 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -2013,12 +2013,11 @@ static enum scan_result try_collapse_pte_mapped_thp(struct mm_struct *mm, unsign /* step 4: remove empty page table */ if (!pml) { pml = pmd_lock(mm, pmd); - if (ptl != pml) { + if (ptl != pml) spin_lock_nested(ptl, SINGLE_DEPTH_NESTING); - if (unlikely(!pmd_same(pgt_pmd, pmdp_get_lockless(pmd)))) { - flush_tlb_mm(mm); - goto unlock; - } + if (unlikely(!pmd_same(pgt_pmd, pmdp_get_lockless(pmd)))) { + flush_tlb_mm(mm); + goto unlock; } } pgt_pmd = pmdp_collapse_flush(vma, haddr, pmd); -- 2.43.0