From: Johannes Weiner <[email protected]>
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 <[email protected]>
Signed-off-by: Johannes Weiner <[email protected]>
---
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