The patch titled Subject: memory-hotplug: bug fix race between isolation and allocation has been removed from the -mm tree. Its filename was memory-hotplug-bug-fix-race-between-isolation-and-allocation.patch This patch was dropped because it was merged into mainline or a subsystem tree ------------------------------------------------------ From: Minchan Kim <minchan@xxxxxxxxxx> Subject: memory-hotplug: bug fix race between isolation and allocation Like below, memory-hotplug makes race between page-isolation and page-allocation so it can hit BUG_ON in __offline_isolated_pages. CPU A CPU B start_isolate_page_range set_migratetype_isolate spin_lock_irqsave(zone->lock) free_hot_cold_page(Page A) /* without zone->lock */ migratetype = get_pageblock_migratetype(Page A); /* * Page could be moved into MIGRATE_MOVABLE * of per_cpu_pages */ list_add_tail(&page->lru, &pcp->lists[migratetype]); set_pageblock_isolate move_freepages_block drain_all_pages /* Page A could be in MIGRATE_MOVABLE of free_list. */ check_pages_isolated __test_page_isolated_in_pageblock /* * We can't catch freed page which * is free_list[MIGRATE_MOVABLE] */ if (PageBuddy(page A)) pfn += 1 << page_order(page A); /* So, Page A could be allocated */ __offline_isolated_pages /* * BUG_ON hit or offline page * which is used by someone */ BUG_ON(!PageBuddy(page A)); This patch checks page's migratetype in freelist in __test_page_isolated_in_pageblock. So now __test_page_isolated_in_pageblock can check the page caused by above race and can fail of memory offlining. Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> Reviewed-by: Yasuaki Ishimatsu <isimatu.yasuaki@xxxxxxxxxxxxxx> Acked-by: Mel Gorman <mgorman@xxxxxxx> Cc: Xishi Qiu <qiuxishi@xxxxxxxxxx> Cc: Wen Congyang <wency@xxxxxxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/page_isolation.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff -puN mm/page_isolation.c~memory-hotplug-bug-fix-race-between-isolation-and-allocation mm/page_isolation.c --- a/mm/page_isolation.c~memory-hotplug-bug-fix-race-between-isolation-and-allocation +++ a/mm/page_isolation.c @@ -200,8 +200,11 @@ __test_page_isolated_in_pageblock(unsign continue; } page = pfn_to_page(pfn); - if (PageBuddy(page)) + if (PageBuddy(page)) { + if (get_freepage_migratetype(page) != MIGRATE_ISOLATE) + break; pfn += 1 << page_order(page); + } else if (page_count(page) == 0 && get_freepage_migratetype(page) == MIGRATE_ISOLATE) pfn += 1; _ Patches currently in -mm which might be from minchan@xxxxxxxxxx are origin.patch swap-add-a-simple-detector-for-inappropriate-swapin-readahead.patch swap-add-a-simple-detector-for-inappropriate-swapin-readahead-fix.patch mm-memblock-reduce-overhead-in-binary-search.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html