From: Vlastimil Babka <vbabka@xxxxxxx> In DEBUG_VM kernel, we can hit infinite loop for order == 0 in buffered_rmqueue() when check_new_pcp() returns 1, because the bad page is never removed from the pcp list. Fix this by removing the page before retrying. Also we don't need to check if page is non-NULL, because we simply grab it from the list which was just tested for being non-empty. Fixes: http://www.ozlabs.org/~akpm/mmotm/broken-out/mm-page_alloc-defer-debugging-checks-of-freed-pages-until-a-pcp-drain.patch Reported-by: Naoya Horiguchi <n-horiguchi@xxxxxxxxxxxxx> Signed-off-by: Vlastimil Babka <vbabka@xxxxxxx> Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> --- mm/page_alloc.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index f8f3bfc435ee..bb320cde4d6d 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -2609,11 +2609,12 @@ struct page *buffered_rmqueue(struct zone *preferred_zone, page = list_last_entry(list, struct page, lru); else page = list_first_entry(list, struct page, lru); - } while (page && check_new_pcp(page)); - __dec_zone_state(zone, NR_ALLOC_BATCH); - list_del(&page->lru); - pcp->count--; + __dec_zone_state(zone, NR_ALLOC_BATCH); + list_del(&page->lru); + pcp->count--; + + } while (check_new_pcp(page)); } else { /* * We most definitely don't want callers attempting to -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>