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 EBFCD606A31A for ; Sat, 31 Oct 2026 09:48:36 +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=R2bWsRX7; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=c680gRXN DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Cc:To:In-Reply-To:References :Message-Id:Content-Transfer-Encoding:Content-Type:MIME-Version:Subject:Date: From:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Unsubscribe-Post: List-Owner; bh=YHe1ZtAJayVrktC+oIcIv9hMCqgNETJjHBAQ4hVj50U=; b=R2bWsRX73btpkf CjXTzOzE832MaRg9YI7IF8jcgHeScafAZCw+yJyEsHUh8kvs732VvxKP6BanxY8BEaLIejtg31n0Q CyHBuRb8zBmFLvaZlGCFcZZ1ZBHooJuBS4La+gZe3dCEVyL+CZCy9S7vrqFGF+QSgMLGteAfMth62 k1D9goNf3rDQOcVstzuK3LwVvz1ss5Mjf9GAMzIz3E7E6PsqrnaFQs44aGP9yuNtQXpLK+IFaoA/f Ip3xpNwWSTjBWRS7xnBW5lu/kQe3JoE/2dkFbxh++6ExkrZ9+AzQf3I7VzMLG8Mtnji5g6BGHkudd pzNYtOQevgtqaQaAFWFg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xN5hU-0000000DB0O-2k9G; Sat, 31 Oct 2026 09:48:36 +0000 Received: from tor.source.kernel.org ([172.105.4.254]) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xN5hT-0000000DAzy-22C5 for kexec@lists.infradead.org; Sat, 31 Oct 2026 09:48:35 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id AB26D605CF; Sat, 31 Oct 2026 09:48:34 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 61D8F1F000C1; Sat, 31 Oct 2026 09:48:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793440114; bh=YHe1ZtAJayVrktC+oIcIv9hMCqgNETJjHBAQ4hVj50U=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=c680gRXN1S8i2NWT11+qqfJhCsH6sZm3Lgl8IeH2hJ2aV1qzLZQtIe8ZB/S0Y8M4u fN/ZfkmGKaWRQLUfNH59CwiDPnl5tXhgo8CD2EYJIAEsLtjBm4rRe8GJm38fmOmjuL FFXv6XLkluWIuC2aGtTKDBtJbzSA3zIsT4UjaArwgZp431mebT1HiG8P+W6A5AvJ1j xyMsVE2U0KpbxJPGXkloi1TT6aBkxHFddiVm/NixvrDnNSFKwp2dWiy9scRGfSCgIf 5wyb9blmNExkoGtL0VUhhBQtgKS3NSi9uiCInnqcR5ifvCRN0AukPxZBsAGRbFB6tI Ngi7/1neI9RLQ== From: "David Hildenbrand (Arm)" Date: Sat, 31 Oct 2026 10:40:01 +0100 Subject: [PATCH v3 32/47] mm/mremap: fix moving PUD leaves X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261031-fixes_core-v3-32-d6437171ecc3@kernel.org> References: <20261031-fixes_core-v3-0-d6437171ecc3@kernel.org> In-Reply-To: <20261031-fixes_core-v3-0-d6437171ecc3@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, Muhammad Usama Anjum , "David Hildenbrand (Arm)" X-Mailer: b4 0.16.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=2279; i=david@kernel.org; h=from:subject:message-id; bh=yDC0RTefMrDLgTK9qV0M/e1RR0BKaMeuZ5BjV9QtmSQ=; b=owGbwMvMwCF2/OVpCdfQ3ZWMp9WSGLKebs8MndYZbbZZdftFjSuZ9ms2y146fHvrmjOOU3Uzv mccUXBe0lHKwiDGwSArpsgSFHzf4OXLdbXVbnzMMHNYmUCGMHBxCsBEjn5m+KdRKHbDdvvW6CkH kuZtmpttl3HlxIzcUG8tAf0dp2/k94YyMpwP/WSvviF49lHx24JPNvidbp4Xsbt7e4hGjZWt9ek L75gA X-Developer-Key: i=david@kernel.org; a=openpgp; fpr=1BD9CAAD735C4C3A460DFCCA4DDE10F700FF835A X-BeenThere: kexec@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "kexec" X-Spam-Status: No, score=-18.9 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,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 From: Josef Bacik pud_none_or_clear_bad() only really works on page tables. PUD leaves confuse the check and make us clear the page table entry and print a warning. Since commit aed877c2b4257 ("device/dax: properly refcount device dax pages when mapping"), this also leaks device-DAX folio references, mapcounts and RSS accounting, resulting in "Bad rss-counter state" warnings on exit. Allow PUD leaves in get_old_pud(). If a PUD leaf cannot be moved as a whole or the move fails, split it. This unmaps it with proper accounting instead of treating the leaf entry as a PMD table. Keep using pud_trans_huge() for now, in the future this code should be cleaned up to just check for PUD leaves. Fix generated by an LLM and sent by Josef Bacik in private. Fixes: a00cc7d9dd93 ("mm, x86: add support for PUD-sized transparent hugepages") Cc: stable@vger.kernel.org Signed-off-by: Josef Bacik Reviewed-by: Lorenzo Stoakes (ARM) [ david: fallthrough after splitting ] Reviewed-by: Pedro Falcato Tested-by: Muhammad Usama Anjum Signed-off-by: David Hildenbrand (Arm) --- mm/mremap.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/mm/mremap.c b/mm/mremap.c index 91f0865f6aeea..1237718848f5c 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -87,7 +87,7 @@ static pud_t *get_old_pud(struct mm_struct *mm, unsigned long addr) return NULL; pud = pud_offset(p4d, addr); - if (pud_none_or_clear_bad(pud)) + if (!pud_trans_huge(*pud) && pud_none_or_clear_bad(pud)) return NULL; return pud; @@ -847,11 +847,10 @@ unsigned long move_page_tables(struct pagetable_move_control *pmc) if (!new_pud) break; if (pud_trans_huge(*old_pud)) { - if (extent == HPAGE_PUD_SIZE) { - move_pgt_entry(pmc, HPAGE_PUD, old_pud, new_pud); - /* We ignore and continue on error? */ + if (extent == HPAGE_PUD_SIZE && + move_pgt_entry(pmc, HPAGE_PUD, old_pud, new_pud)) continue; - } + split_huge_pud(pmc->old, old_pud, pmc->old_addr); } else if (IS_ENABLED(CONFIG_HAVE_MOVE_PUD) && extent == PUD_SIZE) { if (move_pgt_entry(pmc, NORMAL_PUD, old_pud, new_pud)) continue; -- 2.43.0