From: Yizhuo <yzhai003@ucr.edu> To: unlisted-recipients:; (no To-header on input) Cc: csong@cs.ucr.edu, zhiyunq@cs.ucr.edu, Yizhuo <yzhai003@ucr.edu>, Johannes Weiner <hannes@cmpxchg.org>, Michal Hocko <mhocko@kernel.org>, Vladimir Davydov <vdavydov.dev@gmail.com>, cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH] mm/memcg: return value of the function mem_cgroup_from_css() is not checked Date: Wed, 21 Aug 2019 23:22:09 -0700 [thread overview] Message-ID: <20190822062210.18649-1-yzhai003@ucr.edu> (raw) 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@ucr.edu> --- 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
WARNING: multiple messages have this Message-ID (diff)
From: Yizhuo <yzhai003@ucr.edu> Cc: csong@cs.ucr.edu, zhiyunq@cs.ucr.edu, Yizhuo <yzhai003@ucr.edu>, Johannes Weiner <hannes@cmpxchg.org>, Michal Hocko <mhocko@kernel.org>, Vladimir Davydov <vdavydov.dev@gmail.com>, cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH] mm/memcg: return value of the function mem_cgroup_from_css() is not checked Date: Wed, 21 Aug 2019 23:22:09 -0700 [thread overview] Message-ID: <20190822062210.18649-1-yzhai003@ucr.edu> (raw) 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@ucr.edu> --- 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
next reply other threads:[~2019-08-22 6:21 UTC|newest] Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-08-22 6:22 Yizhuo [this message] 2019-08-22 6:22 ` [PATCH] mm/memcg: return value of the function mem_cgroup_from_css() is not checked Yizhuo 2019-08-22 7:05 ` Michal Hocko 2019-08-22 20:07 ` Yizhuo Zhai 2019-08-22 20:12 ` Michal Hocko 2019-08-30 22:27 ` Yizhuo Zhai 2019-08-30 22:27 ` Yizhuo Zhai
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