Hi Wanpeng, On 06/11/2012 09:23 AM, Wanpeng Li wrote: > On Mon, Jun 11, 2012 at 09:17:51AM +0900, Minchan Kim wrote: >> d179e84ba fixed the problem[1] in vmscan.c but same problem is here. >> Let's fix it. >> >> [1] http://comments.gmane.org/gmane.linux.kernel.mm/65844 >> >> I copy and paste d179e84ba's contents for description. >> >> "It is unsafe to run page_count during the physical pfn scan because >> compound_head could trip on a dangling pointer when reading >> page->first_page if the compound page is being freed by another CPU." >> >> Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx> >> Cc: Mel Gorman <mgorman@xxxxxxx> >> Cc: Michal Hocko <mhocko@xxxxxxx> >> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> >> Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx> >> --- >> mm/page_alloc.c | 6 +++++- >> 1 file changed, 5 insertions(+), 1 deletion(-) >> >> diff --git a/mm/page_alloc.c b/mm/page_alloc.c >> index 266f267..019c4fe 100644 >> --- a/mm/page_alloc.c >> +++ b/mm/page_alloc.c >> @@ -5496,7 +5496,11 @@ __count_immobile_pages(struct zone *zone, struct page *page, int count) >> continue; >> >> page = pfn_to_page(check); >> - if (!page_count(page)) { >> + /* >> + * We can't use page_count withou pin a page > ^ > without I will resend fixed version after reviewer comment out. Thanks! -- Kind regards, Minchan Kim -- 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>