Inside function mem_cgroup_wb_domain(), the pointer memcg
could be NULL via mem_cgroup_from_css(). However, this pointer is
not checked and directly dereferenced in the if statement,
which is potentially unsafe.
Signed-off-by: Yizhuo <yzhai003@xxxxxxx>
---
mm/memcontrol.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 661f046ad318..bd84bdaed3b0 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3665,7 +3665,7 @@ struct wb_domain *mem_cgroup_wb_domain(struct bdi_writeback *wb)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(wb->memcg_css);
- if (!memcg->css.parent)
+ if (!memcg || !memcg->css.parent)
return NULL;
return &memcg->cgwb_domain;
--
2.17.1
