The patch titled
memcg: fix refcnt handling at swapoff
has been added to the -mm tree. Its filename is
memcg-fix-refcnt-handling-at-swapoff.patch
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*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://userweb.kernel.org/~akpm/stuff/added-to-mm.txt to find
out what to do about this
The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: memcg: fix refcnt handling at swapoff
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Now, at swapoff, even while try_charge() fails, commit is executed. This
is a bug which turns the refcnt of cgroup_subsys_state negative.
Reported-by: Li Zefan <lizf@xxxxxxxxxxxxxx>
Tested-by: Li Zefan <lizf@xxxxxxxxxxxxxx>
Tested-by: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Reviewed-by: Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx>
Cc: Balbir Singh <balbir@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/swapfile.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff -puN mm/swapfile.c~memcg-fix-refcnt-handling-at-swapoff mm/swapfile.c
--- a/mm/swapfile.c~memcg-fix-refcnt-handling-at-swapoff
+++ a/mm/swapfile.c
@@ -698,8 +698,10 @@ static int unuse_pte(struct vm_area_stru
pte_t *pte;
int ret = 1;
- if (mem_cgroup_try_charge_swapin(vma->vm_mm, page, GFP_KERNEL, &ptr))
+ if (mem_cgroup_try_charge_swapin(vma->vm_mm, page, GFP_KERNEL, &ptr)) {
ret = -ENOMEM;
+ goto out_nolock;
+ }
pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
if (unlikely(!pte_same(*pte, swp_entry_to_pte(entry)))) {
@@ -723,6 +725,7 @@ static int unuse_pte(struct vm_area_stru
activate_page(page);
out:
pte_unmap_unlock(pte, ptl);
+out_nolock:
return ret;
}
_
Patches currently in -mm which might be from kamezawa.hiroyu@xxxxxxxxxxxxxx are
origin.patch
cgroups-use-hierarchy-mutex-in-creation-failure-path.patch
memcg-get-put-parents-at-create-free.patch
memcg-get-put-parents-at-create-free-fix.patch
memcg-fix-refcnt-handling-at-swapoff.patch
proc-pid-maps-dont-show-pgoff-of-pure-anon-vmas.patch
proc-pid-maps-dont-show-pgoff-of-pure-anon-vmas-checkpatch-fixes.patch
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