From: Hugh Dickins Date: Thu, 19 Apr 2012 06:34:46 +0000 (-0700) Subject: memcg: fix Bad page state after replace_page_cache X-Git-Tag: v3.3.3~19 X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=e31c1287e43fb65773fba0e9f2b2ec418268a45d;p=karo-tx-linux.git memcg: fix Bad page state after replace_page_cache commit 9b7f43afd417a6feb80841d30ced4051c362eb5d upstream. My 9ce70c0240d0 "memcg: fix deadlock by inverting lrucare nesting" put a nasty little bug into v3.3's version of mem_cgroup_replace_page_cache(), sometimes used for FUSE. Replacing __mem_cgroup_commit_charge_lrucare() by __mem_cgroup_commit_charge(), I used the "pc" pointer set up earlier: but it's for oldpage, and needs now to be for newpage. Once oldpage was freed, its PageCgroupUsed bit (cleared above but set again here) caused "Bad page state" messages - and perhaps worse, being missed from newpage. (I didn't find this by using FUSE, but in reusing the function for tmpfs.) Signed-off-by: Hugh Dickins Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- diff --git a/mm/memcontrol.c b/mm/memcontrol.c index cd412fc9b802..6fe7afe66a7f 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3350,6 +3350,7 @@ void mem_cgroup_replace_page_cache(struct page *oldpage, * the newpage may be on LRU(or pagevec for LRU) already. We lock * LRU while we overwrite pc->mem_cgroup. */ + pc = lookup_page_cgroup(newpage); __mem_cgroup_commit_charge(memcg, newpage, 1, pc, type, true); }