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=1793306482; b=DTGHcc6dwCEqrJ0ZMLzuquY3SohWccpYnsURHyZJE8NxNSSTPxGB6QIiCX1C17UR1WTq kTlBlZS7iR8Q9xJW6DeKUuKAfyMshfkO0R7fnVVJDbpwxxFAtgcEyoruZW1eQ7ZddKsKl la2QMwmIGQf+ln3CbnHh13VpQwp5a23mlHOI1aMr7hm5jAd7D9LOq+quAo6W8dO1XWRSI d3JYs7csS7GdpFXYNiWr92td+Av354SlKtelalwZuPfr3wuusL9vW5tLoP3GXLZ1cMmW4 0Q97LGzPreI80vv9lrHKu1LLlclkzOoNnGxp+Ubxsc4B+28Kzxh9Mlk7l6IpvsjDfoQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793306482; h=Received:DKIM-Signature:From:Date:Subject:MIME-Version:Content-Type: Content-Transfer-Encoding:Message-Id:References:In-Reply-To:To:Cc: X-Mailer:X-Developer-Signature:X-Developer-Key; bh=6dCA7l8Qcb+zVMAoQ+u8vRDzaCWYfUWbDIcwuPkJnxE=; b=TUsbVvNMYXvYW6DNnbYeyZGf+K693QVr8JFldbg2REZcizKN1fUZCYH71Wkro8iENN3u xr193o3ngmYdEC/nDSMsGbScBjm3Bgk7G7DPr5+RjNdHAMgwQfFlBebCNeBAfj8j8vu05 e+T6be6eZLB6GMFZKNXlogMy8q079+2CSoQ0hFTqz1DrWhBQVKN1bZYSA07c+s9yOwIR4 SenWgZPJXTFuI7axtfcJrB8roA82DaGeSKwGE8ydg5cyfcnsBR3lPCQN17jZkPy930Ey9 2W/hbyGMxEAJWS5K0HdDQ6JOBWiCPKlvAzt/nabXorylBiXMfR+xqeS363I4LDMpsFA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b="Cs7/GV6p"; 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 512EB606A31E; Thu, 29 Oct 2026 20:41:22 +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=Cs7/GV6p Received: by smtp.kernel.org (Postfix) with ESMTPSA id A9C4C1F01824; Thu, 29 Oct 2026 20:41:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793306481; bh=6dCA7l8Qcb+zVMAoQ+u8vRDzaCWYfUWbDIcwuPkJnxE=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=Cs7/GV6pq6eMLJFnqbR9+QKwK6ShcOEk4QCMZXclq06zJpivW8mGEnMOZW9YEUEFr me7PFVPeK46BJU1hjQNgFbL9/Ot6d2rPuJ6UQP4THorxpWzVRPECaHsgmeLmeQaRON Qz3YkhJPUWzx9FFcChAKrp6TTNfjeGiMQn3b2VQ+bZ35CbukcS1MZ9fuoJYnDyK6lG AUytHBl6JsN8niXhnFNeFcHIlaRbkFht1w9q9lGzvdPO5tqDfSobnLfmLK7CA9Um/U /nVJ+0XtYKdEenTS0MtJI5vr91YRIY3EYdRZLofvgfQHN7xXwyvcFndR9Tor8730zm oJFwe5HvlcUCg== From: "David Hildenbrand (Arm)" Date: Thu, 29 Oct 2026 21:33:27 +0100 Subject: [PATCH v2 32/47] mm/mremap: fix moving PUD leaves X-Mailing-List: linux-arch@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20261029-fixes_core-v2-32-a64ce7f83abb@kernel.org> References: <20261029-fixes_core-v2-0-a64ce7f83abb@kernel.org> In-Reply-To: <20261029-fixes_core-v2-0-a64ce7f83abb@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=2222; i=david@kernel.org; h=from:subject:message-id; bh=/15IZZT8ry+ExEMoaMWjieutil1+NN7piBMJHRZeGuI=; b=owGbwMvMwCF2/OVpCdfQ3ZWMp9WSGLIer+3odp3/SFVqszD/9KmpUY5brG9yzZ8jcP7lKREXI 8UDqbdLOkpZGMQ4GGTFFFmCgu8bvHy5rrbajY8ZZg4rE8gQBi5OAZjIG2FGhi0fIzf8PaAuzKQZ dYKBuzLwhYbeshPx4vtiqgxnXdy2z5aR4doFmTtHUgTvnzzV//uy0tLr5xwkZ8wVz4721PU8ELn WkhEA X-Developer-Key: i=david@kernel.org; a=openpgp; fpr=1BD9CAAD735C4C3A460DFCCA4DDE10F700FF835A 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 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 91f0865f6aee..1237718848f5 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