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=1794273823; b=3VWpRSW8/7C+BB9O6ujAPYRb9iYWW0bTTrv21sSTnAkXpILcT75fkHx2KhElBuoEdIML J2v100BEIFyfxJulVJz+KdFgtIjCFFI/SNjZmIzGh5acs06dOATPVmEygzWelGNs4BQsE MRxlvqrjOS0pLVei5IAcJxTCsqoTQRe8TgLhZrBa8ERxf960T59yA0nRlroRqyz2Wopd+ 6Lq1c90KqsGzLbVQITbnYS3OoVSFS8gnJHRydzuidD81Wg5v+WUyculXpkQuzE5m2qUqY eVJ2G+VbNDPm738tygnawsbLu6Znt33MLvs/aS7zWe1Q9W2JyVHf30Nq5Q3YrdcU2BQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794273823; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: MIME-Version:Content-Type:Content-Transfer-Encoding; bh=sSiL9+7wOICTBtG8VdDl4xttBMj1t23tblUqs6agIHY=; b=IPEis4OzQfBEM5CJAF4qmkabNCf629E6H9q+bd+e/6VXdComjkybnZireKqvrhiTO/YO vvZjBFObys9gVLsCWUshqlg7Ti2gepU7ZqvU4Wq2imMoNCwg/WTv+BQ8SkbltcTaj/sP4 n1J4ikPrqDT2lbyL4VwQpcAKqhJBRJBruCZocq6zcfCIyWoxUTkFc2SJODdtRQ3vQmwV8 9b2v0s1d76TrpzGmiu3R4wCCGXPDHiFb4x/Fg2bgiG9oUGKjh0lyvKwbmFyFVw32voqls ayCWclmwj6FGzTXz3NSZQ3MBy12iuf+xWZNfLVGc0jXiMerYHx6ik6pByVCZchrYVxw== 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=fvZVkq5R; 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 7154F606A336 for ; Tue, 10 Nov 2026 01:23:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=fvZVkq5R Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7CC6D1F0089F; Tue, 10 Nov 2026 01:23:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794273823; bh=sSiL9+7wOICTBtG8VdDl4xttBMj1t23tblUqs6agIHY=; h=From:To:Cc:Subject:Date; b=fvZVkq5RC8XBOd0lVnadovJ9mFEdBH60djwqxwp9mtQJehh1M0lww9wqZENFfNDsD efkJZyyikFT4Ag3Lpab8DOK+pS/gIDnyfJphyPg3NuOmUwyhzm1jZ0fkpjq5/pEN4k qDSfpBJiDImj4K2iy6Fonmy4baygLW18XvsnjATe71edTB8hK+geNmmQ+5faVAZgZR ZfSOyWsdZiq8vbkc+wEjr7PuOsQecWaBs9ksADA9lpSQabWziGrEsHJG9cmX5FU3ZH PgwXoQIouiuudgaffgMtXACbGEgQC/6fB9GyqvKW32fLu5W/oM/lMS7/y0XqB991UU 3Xn6Zitgt1clA== From: Sasha Levin To: josef@toxicpanda.com, ljs@kernel.org, pfalcato@suse.de, usama.anjum@arm.com, lance.yang@linux.dev, david@kernel.org Cc: stable@vger.kernel.org Subject: FAILED: patch "[PATCH] mm/mremap: fix moving PUD leaves" failed to apply to 5.15-stable tree Date: Mon, 9 Nov 2026 20:23:41 -0500 Message-ID: <20261109202341-failed-5.15-440c8779757f@kernel.org> X-Mailer: git-send-email 2.53.0 X-Mailing-List: stable@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: 8bit The patch below does not apply to the 5.15-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y git checkout FETCH_HEAD git cherry-pick -x 440c8779757f09f290770b1d361dc1516a9d0b3e # git commit -s git send-email --to '' --in-reply-to '20261109202341-failed-5.15-440c8779757f@kernel.org' --subject-prefix 'PATCH 5.15.y' 'HEAD^..' Thanks, Sasha ------------------ original commit in Linus's tree ------------------ >From 440c8779757f09f290770b1d361dc1516a9d0b3e Mon Sep 17 00:00:00 2001 From: Josef Bacik Date: Sat, 31 Oct 2026 10:40:01 +0100 Subject: [PATCH] mm/mremap: fix moving PUD leaves 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) --- 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; -- 2.53.0