+ mm-page_alloc-add-missing-is_migrate_isolate-check-in-set_page_guard.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm/page_alloc: add missing is_migrate_isolate() check in set_page_guard()
has been added to the -mm mm-unstable branch.  Its filename is
     mm-page_alloc-add-missing-is_migrate_isolate-check-in-set_page_guard.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-add-missing-is_migrate_isolate-check-in-set_page_guard.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@huawei.com>
Subject: mm/page_alloc: add missing is_migrate_isolate() check in set_page_guard()
Date: Fri, 16 Sep 2022 15:22:49 +0800

In MIGRATE_ISOLATE case, zone freepage state shouldn't be modified as
caller will take care of it.  Add missing is_migrate_isolate() here to
avoid possible unbalanced freepage state.  This would happen if someone
isolates the block, and then we face an MCE failure/soft-offline on a page
within that block.  __mod_zone_freepage_state() will be triggered via
below call trace which already had been triggered back when block was
isolated:

take_page_off_buddy
  break_down_buddy_pages
    set_page_guard

Link: https://lkml.kernel.org/r/20220916072257.9639-9-linmiaohe@huawei.com
Fixes: 06be6ff3d2ec ("mm,hwpoison: rework soft offline for free pages")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/page_alloc.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/mm/page_alloc.c~mm-page_alloc-add-missing-is_migrate_isolate-check-in-set_page_guard
+++ a/mm/page_alloc.c
@@ -873,7 +873,8 @@ static inline bool set_page_guard(struct
 	INIT_LIST_HEAD(&page->buddy_list);
 	set_page_private(page, order);
 	/* Guard pages are not available for any usage */
-	__mod_zone_freepage_state(zone, -(1 << order), migratetype);
+	if (!is_migrate_isolate(migratetype))
+		__mod_zone_freepage_state(zone, -(1 << order), migratetype);
 
 	return true;
 }
_

Patches currently in -mm which might be from linmiaohe@huawei.com 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