]> git.proxmox.com Git - mirror_ubuntu-disco-kernel.git/commit
mm: do not use page_count() without a page pin
authorMinchan Kim <minchan@kernel.org>
Tue, 31 Jul 2012 23:42:59 +0000 (16:42 -0700)
committerLinus Torvalds <torvalds@linux-foundation.org>
Wed, 1 Aug 2012 01:42:42 +0000 (18:42 -0700)
commit97d255c816946388bab504122937730d3447c612
tree828927fe44ebb6c0bd6cfd2a0da36b68ed45b4ba
parentde34d965a80d0f61a354bdefa0b15a88bcff2028
mm: do not use page_count() without a page pin

d179e84ba ("mm: vmscan: do not use page_count without a page pin") fixed
this problem in vmscan.c but same problem is in __count_immobile_pages().

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."

Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.cz>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Wanpeng Li <liwp.linux@gmail.com>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mm/page_alloc.c