From: Rei Yamamoto Date: Fri, 13 May 2022 23:48:57 +0000 (-0700) Subject: mm, compaction: fast_find_migrateblock() should return pfn in the target zone X-Git-Tag: v6.1-rc5~1253^2~56 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=bbe832b9db2e1ad21522f8f0bf02775fff8a0e0e;p=platform%2Fkernel%2Flinux-starfive.git mm, compaction: fast_find_migrateblock() should return pfn in the target zone At present, pages not in the target zone are added to cc->migratepages list in isolate_migratepages_block(). As a result, pages may migrate between nodes unintentionally. This would be a serious problem for older kernels without commit a984226f457f849e ("mm: memcontrol: remove the pgdata parameter of mem_cgroup_page_lruvec"), because it can corrupt the lru list by handling pages in list without holding proper lru_lock. Avoid returning a pfn outside the target zone in the case that it is not aligned with a pageblock boundary. Otherwise isolate_migratepages_block() will handle pages not in the target zone. Link: https://lkml.kernel.org/r/20220511044300.4069-1-yamamoto.rei@jp.fujitsu.com Fixes: 70b44595eafe ("mm, compaction: use free lists to quickly locate a migration source") Signed-off-by: Rei Yamamoto Reviewed-by: Miaohe Lin Acked-by: Mel Gorman Reviewed-by: Oscar Salvador Cc: Don Dutile Cc: Wonhyuk Yang Cc: Rei Yamamoto Cc: Signed-off-by: Andrew Morton --- diff --git a/mm/compaction.c b/mm/compaction.c index 0e0ef9e..1f89b96 100644 --- a/mm/compaction.c +++ b/mm/compaction.c @@ -1848,6 +1848,8 @@ static unsigned long fast_find_migrateblock(struct compact_control *cc) update_fast_start_pfn(cc, free_pfn); pfn = pageblock_start_pfn(free_pfn); + if (pfn < cc->zone->zone_start_pfn) + pfn = cc->zone->zone_start_pfn; cc->fast_search_fail = 0; found_block = true; set_pageblock_skip(freepage);