From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794590415; b=PZnQpwtwEH0htSnBEWZ2lJnZgy6qfo22bojPXu/czs44RphAMGQmaw0r+PLcvP7yF0Ps 05X0Wsb8iHIZe1/C+grJJG1ineAJjHZaQPbgKEms4bIYvIhvaKvxK0CCUGNrdOsHBRl2c nPtrYP/jA/TIWLwSdX3XQB6R5mxg7PwYGoysdAfEjbQAKIQrvdVF1I4VC9bc8EKAMYPgB fo765usanNFXZPUtq1TUJtS+31bipW8hV7SG/sUNoo8Oz53d+AmzNKepLDNOztGg25q7R v749UHMehoLwdxvgOZBHOw2flf0RqyTdxHjauM4pImHMCqRnGrGu4Qxm7xwDGKq2AfQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794590415; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=R2XH0jnFsIIIUrhUyHbVDDw5NFj9oMDe7Ou1k+rZ0PA=; b=vzWGvnUc+nj++l7olBz9mKzDx2imo6YXYuH1DL73JC4b9zOCgTlF5mud1y5pFI3XDMzM aBU3ADq3AQpcbm39WOFyokTEH0+Eg5Anc8O/55yHRzZYO05kR5hNv9MVv3WYcMlRG//EF djsN6JlOo9w2+iQTWLI9lsaDNIXIkmTTOCHk1mnIiDlQdYrpg/0BpHirj+Go4s35CIGJK GBOLbdFSf5pAUwKE0krXAAK/QeH7GLBZYd3KKmYZZQtBeUALIw2fCt+xfHaAKfV2qIuzY L0p/mdZsK8UWdwGbj+o0zN5v1MNrC3Z9DWvZ3jRhy0tJWoxiuu3wOb8j4N1qXB9wKRA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=w21q9Q1S; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B689E606B470; Fri, 13 Nov 2026 17:20:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=w21q9Q1S Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6834E1F000C4; Fri, 13 Nov 2026 17:20:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794590415; bh=R2XH0jnFsIIIUrhUyHbVDDw5NFj9oMDe7Ou1k+rZ0PA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=w21q9Q1SZE0iON5AEejNqgUh8uDmXxhf20L4PESB3nC6lVx90+dYADFQHAwyqBY02 ekTE8kkTF/ROGdjAgNANiIXTpJ4ruLInY0KxW4c6lZeRJRD0sJ5l/bpJXJHEwV9t4t SaSLPSeL7usSSgas+mndcyNdqcvkQ6Edib1XSroo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Josef Bacik , "Lorenzo Stoakes (ARM)" , Pedro Falcato , Muhammad Usama Anjum , Lance Yang , "David Hildenbrand (Arm)" , Sasha Levin Subject: [PATCH 6.18 381/686] mm/mremap: fix moving PUD leaves Date: Fri, 13 Nov 2026 10:48:34 -0500 Message-ID: <20261113153833.837721418@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261113153820.902362109@linuxfoundation.org> References: <20261113153820.902362109@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Josef Bacik [ Upstream commit 440c8779757f09f290770b1d361dc1516a9d0b3e ] 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 Link: https://patch.msgid.link/20261031-fixes_core-v3-32-d6437171ecc3@kernel.org Reviewed-by: Lance Yang Signed-off-by: David Hildenbrand (Arm) Signed-off-by: Sasha Levin --- mm/mremap.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/mm/mremap.c b/mm/mremap.c index 369e1406854d3..9f7f45281b487 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; @@ -834,11 +834,10 @@ 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; -- 2.53.0