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| author |   Miaohe Lin <linmiaohe@huawei.com> | 2021-11-05 13:42:19 -0700 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@linux-foundation.org> | 2021-11-06 13:30:40 -0700 |
| commit | a500cb342c84a4c4696850304124bc801331c4a8 (patch) | |
| tree | 580639fc2f89bc2b44d9ec84d785013876788b05 /mm/page_isolation.c | |
| parent | mm/page_isolation: fix potential missing call to unset_migratetype_isolate() (diff) | |
| download | linux-dev-a500cb342c84a4c4696850304124bc801331c4a8.tar.xz linux-dev-a500cb342c84a4c4696850304124bc801331c4a8.zip | |
mm/page_isolation: guard against possible putback unisolated page
Isolating a free page in an isolated pageblock is expected to always
work as watermarks don't apply here.
But if __isolate_free_page() failed, due to condition changes, the page
will be left on the free list. And the page will be put back to free
list again via __putback_isolated_page(). This may trigger
VM_BUG_ON_PAGE() on page->flags checking in __free_one_page() if
PageReported is set. Or we will corrupt the free list because
list_add() will be called for pages already on another list.
Add a VM_WARN_ON() to complain about this change.
Link: https://lkml.kernel.org/r/20210914114508.23725-1-linmiaohe@huawei.com
Fixes: 3c605096d315 ("mm/page_alloc: restrict max order of merging on isolated pageblock")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/page_isolation.c')
| -rw-r--r-- | mm/page_isolation.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/mm/page_isolation.c b/mm/page_isolation.c index f93cc63d8fa1..f67c4c70f17f 100644 --- a/mm/page_isolation.c +++ b/mm/page_isolation.c @@ -94,8 +94,13 @@ static void unset_migratetype_isolate(struct page *page, unsigned migratetype) buddy = page + (buddy_pfn - pfn); if (!is_migrate_isolate_page(buddy)) { - __isolate_free_page(page, order); - isolated_page = true; + isolated_page = !!__isolate_free_page(page, order); + /* + * Isolating a free page in an isolated pageblock + * is expected to always work as watermarks don't + * apply here. + */ + VM_WARN_ON(!isolated_page); } } } |