From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6FFF7379C33; Thu, 27 Aug 2026 20:08:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787861309; cv=none; b=VjgYQRxhqDsbQlksLsLSkGLjC/UaOmXoQ3OIeafC2wItrCY1/O8rXbAe+8Ce4WQofejPT1ZS3ZCGx9EJTaxOv1lVU20BwIwpFK9Jv8PZhdL0KSmYt5R76qDFJ5OCnfxZIAG2XenQn4F1swPm12Dtunot/EiTnVLK57gdFjXKDu4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787861309; c=relaxed/simple; bh=49CrmBTXJ/WTzXvxf1DuKPMLE7TJH+cZM6C61o46aJY=; h=Date:To:From:Subject:Message-Id; b=ss7Bizg0+o7bQzP1Fl5c/nEFw3x0Wk9oyD1Oo3Ld3/wpHz2pMfrWCx1+SG0RACb4tLEg64jnzctpkaorhDlUml9jkPiB6t/IdjXdCLgp67SNRkitblCHm5q+XCi/koOR2c/JAezx5coMn9ljnlEt9H0NZ35VVe2AWkI5ZcorBPE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=IwdR5RGx; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="IwdR5RGx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0469F1F000E9; Thu, 27 Aug 2026 20:08:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=korg; t=1787861304; bh=/YUEziEWluRjG2aOf5jIPZe3zDXgWQg3+fpnSo/trgc=; h=Date:To:From:Subject; b=IwdR5RGxtYRNCCwcOvD7HLgHX+atQC5VvkzwtRiEpTIge6rhsyte6MjBgyvU8FChu L8wJrjbAq4P8gliBDK96Nqj+DQVxgvPACWz7RFJFor1dSmG3iU28ymadrx+LTAaq9h OID2hhmzl0y0SobB9GrMWVXSEsL1BgZ0eXyP+8AE= Date: Thu, 27 Aug 2026 13:08:23 -0700 To: mm-commits@vger.kernel.org,tujinjiang@huawei.com,stable@vger.kernel.org,osalvador@suse.de,muchun.song@linux.dev,david@kernel.org,xialonglong@kylinos.cn,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-hotfixes-stable] mm-hugetlb-keep-max_huge_pages-when-dissolving-surplus-folios.patch removed from -mm tree Message-Id: <20260827200824.0469F1F000E9@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: mm/hugetlb: keep max_huge_pages when dissolving surplus folios has been removed from the -mm tree. Its filename was mm-hugetlb-keep-max_huge_pages-when-dissolving-surplus-folios.patch This patch was dropped because it was merged into the mm-hotfixes-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: Longlong Xia Subject: mm/hugetlb: keep max_huge_pages when dissolving surplus folios Date: Fri, 14 Aug 2026 16:30:27 +0800 dissolve_free_hugetlb_folio() can remove a free folio as surplus when its node has surplus pages. In that case remove_hugetlb_folio() decrements both nr_huge_pages and surplus_huge_pages, leaving the persistent pool size unchanged. Updating max_huge_pages as if a persistent folio had been removed can therefore corrupt the persistent pool target and underflow it when max_huge_pages is zero. Keep max_huge_pages unchanged for surplus folios, including the vmemmap restoration rollback path. Link: https://lore.kernel.org/20260814083027.1419487-1-xialonglong2025@163.com Fixes: cb402bbdabca ("mm/hugetlb: fix surplus pages in dissolve_free_huge_page()") Assisted-by: Codex:gpt-5.6-sol Signed-off-by: Longlong Xia Reviewed-by: Muchun Song Cc: David Hildenbrand Cc: Jinjiang Tu Cc: Longlong Xia Cc: Oscar Salvador Cc: Signed-off-by: Andrew Morton --- mm/hugetlb.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/mm/hugetlb.c~mm-hugetlb-keep-max_huge_pages-when-dissolving-surplus-folios +++ a/mm/hugetlb.c @@ -1992,7 +1992,8 @@ retry: if (h->surplus_huge_pages_node[folio_nid(folio)]) adjust_surplus = true; remove_hugetlb_folio(h, folio, adjust_surplus); - h->max_huge_pages--; + if (!adjust_surplus) + h->max_huge_pages--; spin_unlock_irq(&hugetlb_lock); /* @@ -2012,7 +2013,8 @@ retry: if (rc) { spin_lock_irq(&hugetlb_lock); add_hugetlb_folio(h, folio, adjust_surplus); - h->max_huge_pages++; + if (!adjust_surplus) + h->max_huge_pages++; goto out; } } else { _ Patches currently in -mm which might be from xialonglong@kylinos.cn are