diff options
| author | Kefeng Wang <wangkefeng.wang@huawei.com> | 2023-01-29 12:09:45 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-02-09 11:28:21 +0100 |
| commit | b79ba5953f6fdc5559389ad415620bffc24f024b (patch) | |
| tree | c0edabee0c79afb44466ab16827975ee18ebca30 | |
| parent | 139f866e420a97740f12555be7d77ad330619248 (diff) | |
| download | linux-stable-b79ba5953f6fdc5559389ad415620bffc24f024b.tar.gz linux-stable-b79ba5953f6fdc5559389ad415620bffc24f024b.tar.bz2 linux-stable-b79ba5953f6fdc5559389ad415620bffc24f024b.zip | |
mm: memcg: fix NULL pointer in mem_cgroup_track_foreign_dirty_slowpath()
commit ac86f547ca1002aec2ef66b9e64d03f45bbbfbb9 upstream.
As commit 18365225f044 ("hwpoison, memcg: forcibly uncharge LRU pages"),
hwpoison will forcibly uncharg a LRU hwpoisoned page, the folio_memcg
could be NULl, then, mem_cgroup_track_foreign_dirty_slowpath() could
occurs a NULL pointer dereference, let's do not record the foreign
writebacks for folio memcg is null in mem_cgroup_track_foreign_dirty() to
fix it.
Link: https://lkml.kernel.org/r/20230129040945.180629-1-wangkefeng.wang@huawei.com
Fixes: 97b27821b485 ("writeback, memcg: Implement foreign dirty flushing")
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Reported-by: Ma Wupeng <mawupeng1@huawei.com>
Tested-by: Miko Larsson <mikoxyzzz@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: Ma Wupeng <mawupeng1@huawei.com>
Cc: Naoya Horiguchi <naoya.horiguchi@nec.com>
Cc: Shakeel Butt <shakeelb@google.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | include/linux/memcontrol.h | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index e1644a24009c..e03976302956 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -1655,10 +1655,13 @@ void mem_cgroup_track_foreign_dirty_slowpath(struct folio *folio, static inline void mem_cgroup_track_foreign_dirty(struct folio *folio, struct bdi_writeback *wb) { + struct mem_cgroup *memcg; + if (mem_cgroup_disabled()) return; - if (unlikely(&folio_memcg(folio)->css != wb->memcg_css)) + memcg = folio_memcg(folio); + if (unlikely(memcg && &memcg->css != wb->memcg_css)) mem_cgroup_track_foreign_dirty_slowpath(folio, wb); } |