The patch titled
Subject: mm: update the memmap stat before page is freed
has been added to the -mm mm-hotfixes-unstable branch. Its filename is
mm-update-the-memmap-stat-before-page-is-freed.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-update-the-memmap-stat-before-page-is-freed.patch
This patch will later appear in the mm-hotfixes-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx>
Subject: mm: update the memmap stat before page is freed
Date: Tue, 6 Aug 2024 22:14:53 +0000
It is more logical to update the stat before the page is freed, to avoid
use after free scenarios.
Link: https://lkml.kernel.org/r/20240806221454.1971755-1-pasha.tatashin@xxxxxxxxxx
Fixes: 15995a352474 ("mm: report per-page metadata information")
Signed-off-by: Pasha Tatashin <pasha.tatashin@xxxxxxxxxx>
Cc: Albert Ou <aou@xxxxxxxxxxxxxxxxx>
Cc: Alexander Gordeev <agordeev@xxxxxxxxxxxxx>
Cc: Alexandre Ghiti <alexghiti@xxxxxxxxxxxx>
Cc: Alison Schofield <alison.schofield@xxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Ard Biesheuvel <ardb@xxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Baoquan He <bhe@xxxxxxxxxx>
Cc: Björn Töpel <bjorn@xxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Chen Jiahao <chenjiahao16@xxxxxxxxxx>
Cc: Christian Borntraeger <borntraeger@xxxxxxxxxxxxx>
Cc: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: David Rientjes <rientjes@xxxxxxxxxx>
Cc: Dawei Li <dawei.li@xxxxxxxxxxxx>
Cc: Gerald Schaefer <gerald.schaefer@xxxxxxxxxxxxx>
Cc: Heiko Carstens <hca@xxxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Huacai Chen <chenhuacai@xxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Kent Overstreet <kent.overstreet@xxxxxxxxx>
Cc: Luis Chamberlain <mcgrof@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxx>
Cc: Muchun Song <muchun.song@xxxxxxxxx>
Cc: Nam Cao <namcao@xxxxxxxxxxxxx>
Cc: Naveen N Rao <naveen@xxxxxxxxxx>
Cc: Nicholas Piggin <npiggin@xxxxxxxxx>
Cc: Oscar Salvador <osalvador@xxxxxxx>
Cc: Palmer Dabbelt <palmer@xxxxxxxxxxx>
Cc: Paul Walmsley <paul.walmsley@xxxxxxxxxx>
Cc: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Philippe Mathieu-Daudé <philmd@xxxxxxxxxx>
Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Cc: Ryan Roberts <ryan.roberts@xxxxxxx>
Cc: Sourav Panda <souravpanda@xxxxxxxxxx>
Cc: Sven Schnelle <svens@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Thomas Zimmermann <tzimmermann@xxxxxxx>
Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Cc: WANG Xuerui <kernel@xxxxxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Yi Zhang <yi.zhang@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/hugetlb_vmemmap.c | 4 ++--
mm/page_ext.c | 8 ++++----
2 files changed, 6 insertions(+), 6 deletions(-)
--- a/mm/hugetlb_vmemmap.c~mm-update-the-memmap-stat-before-page-is-freed
+++ a/mm/hugetlb_vmemmap.c
@@ -185,11 +185,11 @@ static int vmemmap_remap_range(unsigned
static inline void free_vmemmap_page(struct page *page)
{
if (PageReserved(page)) {
- free_bootmem_page(page);
mod_node_page_state(page_pgdat(page), NR_MEMMAP_BOOT, -1);
+ free_bootmem_page(page);
} else {
- __free_page(page);
mod_node_page_state(page_pgdat(page), NR_MEMMAP, -1);
+ __free_page(page);
}
}
--- a/mm/page_ext.c~mm-update-the-memmap-stat-before-page-is-freed
+++ a/mm/page_ext.c
@@ -330,18 +330,18 @@ static void free_page_ext(void *addr)
if (is_vmalloc_addr(addr)) {
page = vmalloc_to_page(addr);
pgdat = page_pgdat(page);
+ mod_node_page_state(pgdat, NR_MEMMAP,
+ -1L * (DIV_ROUND_UP(table_size, PAGE_SIZE)));
vfree(addr);
} else {
page = virt_to_page(addr);
pgdat = page_pgdat(page);
+ mod_node_page_state(pgdat, NR_MEMMAP,
+ -1L * (DIV_ROUND_UP(table_size, PAGE_SIZE)));
BUG_ON(PageReserved(page));
kmemleak_free(addr);
free_pages_exact(addr, table_size);
}
-
- mod_node_page_state(pgdat, NR_MEMMAP,
- -1L * (DIV_ROUND_UP(table_size, PAGE_SIZE)));
-
}
static void __free_page_ext(unsigned long pfn)
_
Patches currently in -mm which might be from pasha.tatashin@xxxxxxxxxx are
mm-update-the-memmap-stat-before-page-is-freed.patch
mm-keep-nid-around-during-hot-remove.patch
memcg-increase-the-valid-index-range-for-memcg-stats-v5.patch
vmstat-kernel-stack-usage-histogram.patch
task_stack-uninline-stack_not_used.patch
