Hi all,
On Wed, 25 Nov 2020 20:15:11 +0800 Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx> wrote:
>
> Acked-by: Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx>
>
>
> 在 2020/11/25 下午7:22, Lorenzo Stoakes 写道:
> > Move memcg check to mem_cgroup_page_lruvec() as there are callers which
> > may invoke this with !memcg in mem_cgroup_lruvec(), whereas they should
> > not in mem_cgroup_page_lruvec().
> >
> > We expect that we have always charged a page to the memcg before
> > mem_cgroup_page_lruvec() is invoked, so add a warning to assert that this
> > is the case.
> >
> > Signed-off-by: Lorenzo Stoakes <lstoakes@xxxxxxxxx>
> > Reported-by: syzbot+ce635500093181f39c1c@xxxxxxxxxxxxxxxxxxxxxxxxx
> > ---
> > include/linux/memcontrol.h | 6 ++++--
> > 1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> > index 87ed56dc75f9..3e6a1df3bdb9 100644
> > --- a/include/linux/memcontrol.h
> > +++ b/include/linux/memcontrol.h
> > @@ -618,7 +618,6 @@ static inline struct lruvec *mem_cgroup_lruvec(struct mem_cgroup *memcg,
> > goto out;
> > }
> >
> > - VM_WARN_ON_ONCE(!memcg);
> > if (!memcg)
> > memcg = root_mem_cgroup;
> >
> > @@ -645,7 +644,10 @@ static inline struct lruvec *mem_cgroup_lruvec(struct mem_cgroup *memcg,
> > static inline struct lruvec *mem_cgroup_page_lruvec(struct page *page,
> > struct pglist_data *pgdat)
> > {
> > - return mem_cgroup_lruvec(page_memcg(page), pgdat);
> > + struct mem_cgroup *memcg = page_memcg(page);
> > +
> > + VM_WARN_ON_ONCE_PAGE(!memcg, page);
> > + return mem_cgroup_lruvec(memcg, pgdat);
> > }
> >
> > static inline bool lruvec_holds_page_lru_lock(struct page *page,
> >
I have added that patch to the akpm tree in linux-next today as a fix
for "mm/memcg: add missed warning in mem_cgroup_lruvec".
Andrew: the original patch is here:
https://lore.kernel.org/lkml/20201125112202.387009-1-lstoakes@xxxxxxxxx/
--
Cheers,
Stephen Rothwell
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