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authorHugh Dickins <hughd@google.com>2012-04-18 23:34:46 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-04-18 23:40:57 -0700
commit9b7f43afd417a6feb80841d30ced4051c362eb5d (patch)
tree695f97a4d028a3463c8e7edaa4c6d410a941d0bb /mm
parent932e9f352b5d685725076f21b237f7c7d804b29c (diff)
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 <hughd@google.com> Cc: stable@vger.kernel.org [v3.3 only] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/memcontrol.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index a7165a60d0a7..b868def9bcc1 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);
}