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=1794270250; b=KWcYLDOZ7QA7seuZq3LS6mHRjBd1aosm5eQK3wS2uBErhLhnoziZYS3X+tMJFHDA6Tse o5+cEFzSlo/soEqSzd866cBecLeI4//aAaGRW/VXF4TLdOIe0+j29FcGQwHsOnlY1Tlht O61co/0P60jMScrtF7OlZgGk/AU6o1SSUajh04OQPBfM+hMSPdDhgFEzuLWZOqAD7mt0e iFHp1LcBGl4yw5loIm2HT86vnvoWc0ux3O+5SBwrZhVIshYcpoVoFwtO7G5NiqolxEEQI UqX1NOFgsyoLMf39q0eAYzh8YrBM3KV+PFjKJiJ98T9nVFHhuxDNN7tUSSAAVuoj2GQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794270250; h=Received:DKIM-Signature:Date:To:From:Subject:Message-Id; bh=BB5yTfkQZuLx+hrNXsXydPDZeBoHyMRfwRL4VXc87SE=; b=BEMEFc4uq2W7rFCqQ9qvMWZ58gXdQ45Zj5MKX4VH02X76fKHZgNZg8NIhJg+WY6IrW3v Wu6q3D/uBoDo2Bf16QDzYVKj65uOnza0IJl9DTrUCBBMO84umjPjL8/H7bfT4QHKYYGoB G8SjO4Z+/BXg5M+IyYB3EdVt0u8+UhyG6XjUswTqtb5M1y5o9o687iB7NgLdHfcSbXLiD 3HNh9ci5dGHIApyT4bbboeGW6JlmJm7TPRTxF+E3xAjW9LwEEwCrJSgyg1dO/fB1KELmD pZGYMvFYkLUwYWpbdN6lbeLO35p0U2OcGEZkPCKz20UaSMc4exvbUlgnSsaFXeGAzPg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linux-foundation.org header.i=@linux-foundation.org header.a=rsa-sha256 header.s=korg header.b="HWT+j/Wf"; 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 3A2D8606A326 for ; Tue, 10 Nov 2026 00:24:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.a=rsa-sha256 header.s=korg header.b=HWT+j/Wf Received: by smtp.kernel.org (Postfix) with ESMTPSA id DF3601F008A1; Tue, 10 Nov 2026 00:24:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1794270250; bh=BB5yTfkQZuLx+hrNXsXydPDZeBoHyMRfwRL4VXc87SE=; h=Date:To:From:Subject; b=HWT+j/WfUPOkBfW7bQFIvnbmnqrggZDBpcmVbhEEF5aC47IOaHsNjyJpdM2Ta/Hyg QGw92Li8YbreNCokUEkWTaiWb5pAMAESr/KqbkQbsdRNR8V914+m/kIM+P0jcGHhoz JgAbkxdKgopZaTHplnsfe7ET/SMp3TbvcKhu2FnE= Date: Mon, 09 Nov 2026 16:24:09 -0800 To: mm-commits@vger.kernel.org,chengkaitao@kylinos.cn, akpm@linux-foundation.org From: Andrew Morton Subject: + mm-hugetlb-preserve-persistent-flags-when-returning-folios-to-the-pool.patch added to mm-unstable branch Message-Id: <20261110002409.DF3601F008A1@smtp.kernel.org> X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list The patch titled Subject: mm/hugetlb: preserve persistent flags when returning folios to the pool has been added to the -mm mm-unstable branch. Its filename is mm-hugetlb-preserve-persistent-flags-when-returning-folios-to-the-pool.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-hugetlb-preserve-persistent-flags-when-returning-folios-to-the-pool.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via various branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there most days ------------------------------------------------------ From: Kaitao Cheng Subject: mm/hugetlb: preserve persistent flags when returning folios to the pool Date: Fri, 06 Nov 2026 18:05:19 +0800 add_hugetlb_folio() returns a folio to the HugeTLB pool when vmemmap restoration fails. It clears folio->private and restores only HPG_vmemmap_optimized, losing other flags that must survive the rollback. Clearing HPG_cma causes a later free to bypass the CMA release path, leaving the CMA allocation bitmap set. Clearing HPG_raw_hwp_unreliable loses the indication that the locations of poisoned subpages are unknown, undermining the checks that prevent freeing or unpoisoning such folios. Preserve the existing flags instead of resetting folio->private. Callers already clear HPG_restore_reserve, HPG_migratable and HPG_freed before returning a folio to the pool. Clear HPG_temporary in free_huge_folio() before attempting to free a temporary folio, so a failed vmemmap restore does not leave that flag set on a folio returned as surplus. Add a VM_WARN_ON_ONCE_FOLIO() check for flags other than HPG_vmemmap_optimized, HPG_raw_hwp_unreliable and HPG_cma to detect incomplete transient flag cleanup. Link: https://lore.kernel.org/20261106100521.30099-3-kaitao.cheng@linux.dev Fixes: 161df60e9e89 ("mm, hwpoison, hugetlb: support saving mechanism of raw error pages") Fixes: d2d786714080 ("mm/hugetlb: enable bootmem allocation from CMA areas") Signed-off-by: Kaitao Cheng Signed-off-by: Andrew Morton Closes: https://sashiko.dev/#/bug/linux-5363eb09-9c3c-4f8b-9f3c-a998a8c4b258 Suggested-by: David Hildenbrand Suggested-by: Muchun Song Suggested-by: Zi Yan Acked-by: Muchun Song Acked-by: Zi Yan Acked-by: Qi Zheng Cc: Oscar Salvador Cc: Mike Rapoport Cc: Johannes Weiner Cc: Michal Hocko Cc: Roman Gushchin Cc: Shakeel Butt Cc: Mani Tofigh Cc: Mike Kravetz Cc: Baolin Wang Cc: Miaohe Lin Cc: Naoya Horiguchi Cc: Frank van der Linden Cc: Chris Down Cc: Joshua Hahn Cc: "Oscar Salvador (SUSE)" --- mm/hugetlb.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) --- a/mm/hugetlb.c~mm-hugetlb-preserve-persistent-flags-when-returning-folios-to-the-pool +++ a/mm/hugetlb.c @@ -1443,6 +1443,12 @@ void add_hugetlb_folio(struct hstate *h, lockdep_assert_held(&hugetlb_lock); + /* Callers must clear transient flags before returning to the pool. */ + VM_WARN_ON_ONCE_FOLIO((unsigned long)folio->private & + ~(BIT(HPG_vmemmap_optimized) | + BIT(HPG_raw_hwp_unreliable) | + BIT(HPG_cma)), folio); + INIT_LIST_HEAD(&folio->lru); h->nr_huge_pages++; h->nr_huge_pages_node[nid]++; @@ -1453,9 +1459,6 @@ void add_hugetlb_folio(struct hstate *h, } __folio_set_hugetlb(folio); - /* Clear all folio->private flags except hugetlb_vmemmap_optimized. */ - folio->private = NULL; - folio_set_hugetlb_vmemmap_optimized(folio); arch_clear_hugetlb_flags(folio); enqueue_hugetlb_folio(h, folio); @@ -1743,6 +1746,7 @@ void free_huge_folio(struct folio *folio h->resv_huge_pages++; if (folio_test_hugetlb_temporary(folio)) { + folio_clear_hugetlb_temporary(folio); remove_hugetlb_folio(h, folio, false); spin_unlock_irqrestore(&hugetlb_lock, flags); update_and_free_hugetlb_folio(h, folio, true); _ Patches currently in -mm which might be from chengkaitao@kylinos.cn are mm-hugetlb_cma-fix-incorrect-hugetlb_cma_size-assignment-on-malformed-input.patch mm-hugetlb-preserve-persistent-flags-when-returning-folios-to-the-pool.patch mm-hugetlb-fix-nr_hugetlb-accounting-for-unused-surplus-folios.patch mm-hugetlb-account-nr_hugetlb-at-folio-state-transitions.patch