The patch titled
Subject: mm/page_alloc: fix freeing static percpu memory
has been added to the -mm mm-unstable branch. Its filename is
mm-page_alloc-fix-freeing-static-percpu-memory.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-page_alloc-fix-freeing-static-percpu-memory.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Subject: mm/page_alloc: fix freeing static percpu memory
Date: Fri, 16 Sep 2022 15:22:47 +0800
The size of struct per_cpu_zonestat can be 0 on !SMP && !NUMA. In that
case, zone->per_cpu_zonestats will always equal to boot_zonestats. But in
zone_pcp_reset(), zone->per_cpu_zonestats is freed via free_percpu()
directly without checking against boot_zonestats first. boot_zonestats
will be released by free_percpu() unexpectedly.
Link: https://lkml.kernel.org/r/20220916072257.9639-7-linmiaohe@xxxxxxxxxx
Fixes: 28f836b6777b ("mm/page_alloc: split per cpu page lists and zone stats")
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Reviewed-by: Oscar Salvador <osalvador@xxxxxxx>
Cc: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_alloc.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
--- a/mm/page_alloc.c~mm-page_alloc-fix-freeing-static-percpu-memory
+++ a/mm/page_alloc.c
@@ -9505,9 +9505,11 @@ void zone_pcp_reset(struct zone *zone)
drain_zonestat(zone, pzstats);
}
free_percpu(zone->per_cpu_pageset);
- free_percpu(zone->per_cpu_zonestats);
zone->per_cpu_pageset = &boot_pageset;
- zone->per_cpu_zonestats = &boot_zonestats;
+ if (zone->per_cpu_zonestats != &boot_zonestats) {
+ free_percpu(zone->per_cpu_zonestats);
+ zone->per_cpu_zonestats = &boot_zonestats;
+ }
}
}
_
Patches currently in -mm which might be from linmiaohe@xxxxxxxxxx are
mm-hwpoison-use-clearpagehwpoison-in-memory_failure.patch
mm-hwpoison-use-__pagemovable-to-detect-non-lru-movable-pages.patch
mm-hwpoison-use-num_poisoned_pages_sub-to-decrease-num_poisoned_pages.patch
mm-hwpoison-avoid-unneeded-page_mapped_in_vma-overhead-in-collect_procs_anon.patch
mm-hwpoison-check-pagetable-explicitly-in-hwpoison_user_mappings.patch
mm-hwpoison-cleanup-some-obsolete-comments.patch
writeback-remove-unused-macro-dirty_full_scope.patch
mm-page_alloc-ensure-kswapd-doesnt-accidentally-go-to-sleep.patch
mm-page_alloc-make-zone_pcp_update-static.patch
mm-remove-obsolete-macro-nr_pcp_order_mask-and-nr_pcp_order_width.patch
mm-page_alloc-remove-obsolete-comment-in-zone_statistics.patch
mm-page_alloc-add-__init-annotations-to-init_mem_debugging_and_hardening.patch
mm-page_alloc-fix-freeing-static-percpu-memory.patch
mm-remove-obsolete-pgdat_is_empty.patch
mm-page_alloc-add-missing-is_migrate_isolate-check-in-set_page_guard.patch
mm-page_alloc-use-local-variable-zone_idx-directly.patch
mm-memory_hotplug-remove-obsolete-generic_free_nodedata.patch
mm-page_alloc-make-boot_nodestats-static.patch
mm-page_alloc-use-helper-macro-sz_1km.patch
mm-page_alloc-init-local-variable-buddy_pfn.patch
mm-page_alloc-use-costly_order-in-warn_on_once_gfp.patch
mm-page_alloc-remove-obsolete-gfpflags_normal_context.patch
mm-page_alloc-fix-obsolete-comment-in-deferred_pfn_valid.patch
