From: Johannes Weiner <hannes@xxxxxxxxxxx> Mike reports the following crash in -next: [ 28.643019] page:ffffea0004fb4280 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x13ed0a [ 28.645455] flags: 0x200000000000000(node=0|zone=2) [ 28.646835] page_type: 0xffffffff() [ 28.647886] raw: 0200000000000000 dead000000000100 dead000000000122 0000000000000000 [ 28.651170] raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 [ 28.653124] page dumped because: VM_BUG_ON_PAGE(is_migrate_isolate(mt)) [ 28.654769] ------------[ cut here ]------------ [ 28.655972] kernel BUG at mm/page_alloc.c:1231! This VM_BUG_ON() used to check that the cached pcppage_migratetype set by free_unref_page() wasn't MIGRATE_ISOLATE. When I removed the caching, I erroneously changed the assert to check that no isolated pages are on the pcplist. This is quite different, because pages can be isolated *after* they had been put on the freelist already (which is handled just fine). IOW, this was purely a sanity check on the migratetype caching. With that gone, the check should have been removed as well. Do that now. Reported-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx> --- mm/page_alloc.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 123494dbd731..1400e674ab86 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1227,9 +1227,6 @@ static void free_pcppages_bulk(struct zone *zone, int count, count -= nr_pages; pcp->count -= nr_pages; - /* MIGRATE_ISOLATE page should not go to pcplists */ - VM_BUG_ON_PAGE(is_migrate_isolate(mt), page); - __free_one_page(page, pfn, zone, order, mt, FPI_NONE); trace_mm_page_pcpu_drain(page, order, mt); } while (count > 0 && !list_empty(list)); -- 2.41.0
