The patch titled
Subject: mm/page_isolation: fix potential missing call to unset_migratetype_isolate()
has been added to the -mm tree. Its filename is
mm-page_isolation-fix-potential-missing-call-to-unset_migratetype_isolate.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-page_isolation-fix-potential-missing-call-to-unset_migratetype_isolate.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-page_isolation-fix-potential-missing-call-to-unset_migratetype_isolate.patch
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------------------------------------------------------
From: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Subject: mm/page_isolation: fix potential missing call to unset_migratetype_isolate()
In start_isolate_page_range() undo path, pfn_to_online_page() just checks
the first pfn in a pageblock while __first_valid_page() will traverse the
pageblock until the first online pfn is found. So we may miss the call to
unset_migratetype_isolate() in undo path and pages will remain isolated
unexpectedly. Fix this by calling undo_isolate_page_range() and this will
also help to simplify the code further. Note we shouldn't ever trigger it
because MAX_ORDER-1 aligned pfn ranges shouldn't contain memory holes now.
Link: https://lkml.kernel.org/r/20210914114348.15569-1-linmiaohe@xxxxxxxxxx
Fixes: 2ce13640b3f4 ("mm: __first_valid_page skip over offline pages")
Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/page_isolation.c | 20 +++-----------------
1 file changed, 3 insertions(+), 17 deletions(-)
--- a/mm/page_isolation.c~mm-page_isolation-fix-potential-missing-call-to-unset_migratetype_isolate
+++ a/mm/page_isolation.c
@@ -188,7 +188,6 @@ int start_isolate_page_range(unsigned lo
unsigned migratetype, int flags)
{
unsigned long pfn;
- unsigned long undo_pfn;
struct page *page;
BUG_ON(!IS_ALIGNED(start_pfn, pageblock_nr_pages));
@@ -198,25 +197,12 @@ int start_isolate_page_range(unsigned lo
pfn < end_pfn;
pfn += pageblock_nr_pages) {
page = __first_valid_page(pfn, pageblock_nr_pages);
- if (page) {
- if (set_migratetype_isolate(page, migratetype, flags)) {
- undo_pfn = pfn;
- goto undo;
- }
+ if (page && set_migratetype_isolate(page, migratetype, flags)) {
+ undo_isolate_page_range(start_pfn, pfn, migratetype);
+ return -EBUSY;
}
}
return 0;
-undo:
- for (pfn = start_pfn;
- pfn < undo_pfn;
- pfn += pageblock_nr_pages) {
- struct page *page = pfn_to_online_page(pfn);
- if (!page)
- continue;
- unset_migratetype_isolate(page, migratetype);
- }
-
- return -EBUSY;
}
/*
_
Patches currently in -mm which might be from linmiaohe@xxxxxxxxxx are
mm-page_isolation-guard-against-possible-putback-unisolated-page.patch
mm-page_isolation-fix-potential-missing-call-to-unset_migratetype_isolate.patch
mm-memory_hotplug-make-hwpoisoned-dirty-swapcache-pages-unmovable.patch
mm-zsmallocc-close-race-window-between-zs_pool_dec_isolated-and-zs_unregister_migration.patch
mm-zsmallocc-combine-two-atomic-ops-in-zs_pool_dec_isolated.patch
