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=1793057257; b=X8b4JFNqGqjnGiSAFauBFMdlX9LPj9HSFPusgAkl8t7Q95S2W1rAW2dIRQBPz2i0OUE7 5oh2rjEkZ6hAzTyH+izrJ/D97ZACOYotm4x/tLGJXFkczD2JT2/TRuPLr/GOGVAniBU/V UcJ6vPQ8kzPK73cQqKZf8fwDA3kdgwT6SD9SF0mTt1V6S42lU29cLzjBMF60q24GTvEWe EMMb4gwTALbDD9BY7mQyU0PQOQyQe1OoiX+w1LrXxAhtDMhvAKMeqqGoE2hC8LAs+KfUC sHeSxTBsGhApyXavoyRuGXRzG+msG5RoumIh6G36hPfoHcOsGIBdxFqfWjHp6Et7Y3g== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793057257; 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=W7+b44oyozv46Rxfjs2BdSgv4+W+us3N9SjMGx4NrpQ=; b=cHEa4U9j5O7J5lMTIXV3SAR9nuFg8b8JyNnH/C+TSrcXoL0DXWQu9YHmdxLhb3QdIaFm S/fbIJ2/rErva48fRd84X9GAQm7yD4dIf7W2wz3lF52ZfRwV4sUh6k6hzowp8ofOQncYz P5BhPFDr5cn5ur7pbdHltI6icPC6jORK20VVfTM+l5wDXKk6/WyT9pW9VoRo1TQPDmHZo A77KyrUJlVaSjnXz/68shfF2YJrtfhwBBt84/QZSbfEMgBCnb2eGLxdLi366OOfrckMsU 6osO/iUzk9LS2c/c9aqfhVYKb5Juv9HmTT3stYE/evQ8K0nqsjGX+z41x67j/KEuK2Q== 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="evu1XW/7"; 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 98D12606A31F; Mon, 26 Oct 2026 23:27:36 +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=evu1XW/7 Received: by smtp.kernel.org (Postfix) with ESMTPSA id A19781F01825; Mon, 26 Oct 2026 23:27:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793057256; bh=W7+b44oyozv46Rxfjs2BdSgv4+W+us3N9SjMGx4NrpQ=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=evu1XW/7y1R64K47ukh34E+hAs/6HfE3JuNKx2qvcK11wZMq86dZPM3DsMEp/EC+J p82x7dsIx59ezC5CkSB4jD1ZOKsPv598Qz4acNyP3aEwCNi0XShjPBGHlKOv0HV/N4 NSoQGgLBupcZtuemFQo0kEG4lyMup7+do3oA7kILcP3NxBBesLVl0UdbIcKqGpOSx7 VcBkLBkGa/sGXBxgWW7om8v3vJ6tPDxEdfIbxw1jhhUBD/VtoLzaQ8Q1+gcgnUbAxD UeeDOGx05fXjprwHz1vXYI3mcjV2luOlB+4p806KHfYlIbeeXbp48/u/Y/kRdKtHFT duoIbzi2a7gwA== From: "David Hildenbrand (Arm)" Date: Tue, 27 Oct 2026 00:17:51 +0100 Subject: [PATCH 31/46] mm/mremap: fix moving PUD leaves X-Mailing-List: linux-kernel@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: <20261027-fixes_core-v1-31-6f74bec9a5bb@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=2177; i=david@kernel.org; h=from:subject:message-id; bh=xaFHaOsTg/KKNqVl7kj20OnAYFH/hrUerHWjoic7u1E=; b=owGbwMvMwCF2/OVpCdfQ3ZWMp9WSGLLu35/u8LPiwNykGsmlh4tmBoRHZGrmm0hZn8xguGt8+ kZ9foZCRykLgxgHg6yYIktQ8H2Dly/X1Va78THDzGFlAhnCwMUpABPhK2L4Z3xhmcexC+anMk7X 7HWTz59XxGDnY2N+9ivT1mbFWVNeSDIyvI2atG6Ge5X1mqkuar+2vj3snufgxW9T0aN29EaI1A1 LFgA= 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 ] 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