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 2C47442376D; Thu, 16 Jul 2026 14:15:22 +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=1784211324; cv=none; b=jjdC9owd0sseXioG1nNanPeByEHnPXkYyr6/FpDk7BTWjGN97AurqNbqrf1HRHd9fRdunInY16vDC8ukbJYNeSkvT2+qpzmmSkSk53vpFrLLXZCsz68CSzmwIVMyhhS6qceiD3qfb8nCdFjs6vmJxdCRORkJoluR49cDG8lkrYQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784211324; c=relaxed/simple; bh=+22XLIsfYhtc5U3nJOZNDPLh7Q62R9q9P3/bvjYnypM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=kQjfWN02KaVw75hJgae9oIEPklnnSP9wKDvZkrDRly/QJraLEZ/7Y5DE5ky+9wBtiQirMYvWfclarZRXGrVdyn0aLx/Gu+b8ESKLqgPz6pyqvFCuUzmHuQUz3oT2G5J72KBjCH8fOLzRTAoRmJ2Yy/uYWZbPkgZJ1rLF/IE6Wl0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Ie4/Mkp5; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="Ie4/Mkp5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 52E321F000E9; Thu, 16 Jul 2026 14:15:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1784211322; bh=lLNiJPfT+wYJoABwHEyrLHH2uranxStddeuZw/vI880=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Ie4/Mkp5BU17pTboXRbAWgoOaGv0/MudjZxDZzXhNxsOitJF5yqiJfaaWRiEWqcnL 7agknUjAgPLCkXydKD59dGO4KrTKyZhdKI/HeRlXKhrrglB8MUpSLTUhsfo/RiW/zP Wn7uoTIcJ6riA4fyyqJQVTV8UPKjZoCoFfLugzbU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, "David Hildenbrand (Arm)" , Andrew Morton , Dave Hansen , "Mike Rapoport (Microsoft)" , Lance Yang Subject: [PATCH 6.18 385/480] x86/mm: Fix freeing of PMD-sized vmemmap pages Date: Thu, 16 Jul 2026 15:32:12 +0200 Message-ID: <20260716133053.129534983@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260716133044.672218725@linuxfoundation.org> References: <20260716133044.672218725@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: David Hildenbrand (Arm) commit 39406c05f8f150f1685839acd38ffdd69ff92031 upstream. Commit bf9e4e30f353 ("x86/mm: use pagetable_free()"), switched from freeing non-boot page tables through __free_pages() to pagetable_free(). However, the function is also called to free vmemmap pages. Given that vmemmap pages are not page tables, already the page_ptdesc(page) is wrong. But worse, pagetable_free() calls: __free_pages(page, compound_order(page)); Since vmemmap pages are not compound pages (see vmemmap_alloc_block()) -- except for HVO, which doesn't apply here -- only first page of a PMD-sized vmemmap page is freed, leaking the other ones. Fix it by properly decoupling pagetable and vmemmap freeing. free_pagetable() no longer has to mess with SECTION_INFO, as only the vmemmap is marked like that in register_page_bootmem_memmap(). The indentation in remove_pmd_table() is messed up. Fix that while touching it. Bootmem info handling will soon be fixed up. For now, handle it similar to free_pagetable(), just avoiding the ifdef. [ dhansen: changelog munging. More imperative voice ] Fixes: bf9e4e30f353 ("x86/mm: use pagetable_free()") Signed-off-by: David Hildenbrand (Arm) Signed-off-by: Andrew Morton Signed-off-by: Dave Hansen Acked-by: Mike Rapoport (Microsoft) Tested-by: Lance Yang Link: https://lore.kernel.org/20260429-vmemmap-v2-1-8dfcacffd877@kernel.org Link: https://patch.msgid.link/20260429-vmemmap-v2-1-8dfcacffd877@kernel.org Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman --- arch/x86/mm/init_64.c | 40 ++++++++++++++++++++++++++-------------- 1 file changed, 26 insertions(+), 14 deletions(-) --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -1021,7 +1021,7 @@ static void __meminit free_pagetable(str #ifdef CONFIG_HAVE_BOOTMEM_INFO_NODE enum bootmem_type type = bootmem_type(page); - if (type == SECTION_INFO || type == MIX_SECTION_INFO) { + if (type == MIX_SECTION_INFO) { while (nr_pages--) put_page_bootmem(page++); } else { @@ -1035,13 +1035,24 @@ static void __meminit free_pagetable(str } } -static void __meminit free_hugepage_table(struct page *page, +static void __meminit free_vmemmap_pages(struct page *page, unsigned int order, struct vmem_altmap *altmap) { - if (altmap) - vmem_altmap_free(altmap, PMD_SIZE / PAGE_SIZE); - else - free_pagetable(page, get_order(PMD_SIZE)); + unsigned long nr_pages = 1u << order; + + if (altmap) { + vmem_altmap_free(altmap, nr_pages); + } else if (PageReserved(page)) { + if (IS_ENABLED(CONFIG_HAVE_BOOTMEM_INFO_NODE) && + bootmem_type(page) == SECTION_INFO) { + while (nr_pages--) + put_page_bootmem(page++); + } else { + free_reserved_pages(page, nr_pages); + } + } else { + __free_pages(page, order); + } } static void __meminit free_pte_table(pte_t *pte_start, pmd_t *pmd) @@ -1125,7 +1136,8 @@ remove_pte_table(pte_t *pte_start, unsig return; if (!direct) - free_pagetable(pte_page(*pte), 0); + /* We never populate base pages from the altmap. */ + free_vmemmap_pages(pte_page(*pte), 0, NULL); spin_lock(&init_mm.page_table_lock); pte_clear(&init_mm, addr, pte); @@ -1160,19 +1172,19 @@ remove_pmd_table(pmd_t *pmd_start, unsig if (IS_ALIGNED(addr, PMD_SIZE) && IS_ALIGNED(next, PMD_SIZE)) { if (!direct) - free_hugepage_table(pmd_page(*pmd), - altmap); + free_vmemmap_pages(pmd_page(*pmd), + PMD_ORDER, altmap); spin_lock(&init_mm.page_table_lock); pmd_clear(pmd); spin_unlock(&init_mm.page_table_lock); pages++; } else if (vmemmap_pmd_is_unused(addr, next)) { - free_hugepage_table(pmd_page(*pmd), - altmap); - spin_lock(&init_mm.page_table_lock); - pmd_clear(pmd); - spin_unlock(&init_mm.page_table_lock); + free_vmemmap_pages(pmd_page(*pmd), PMD_ORDER, + altmap); + spin_lock(&init_mm.page_table_lock); + pmd_clear(pmd); + spin_unlock(&init_mm.page_table_lock); } continue; }