commit: 9b7f43afd417a6feb80841d30ced4051c362eb5d From: Hugh Dickins <[email protected]> Date: Wed, 18 Apr 2012 23:34:46 -0700 Subject: memcg: fix Bad page state after replace_page_cache
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 <[email protected]> Cc: [email protected] [v3.3 only] Signed-off-by: Linus Torvalds <[email protected]> --- mm/memcontrol.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index a7165a6..b868def 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3392,6 +3392,7 @@ 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); } -- 1.7.3.4 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
