From: Michal Hocko <mhocko@suse.cz>
To: Joonsoo Kim <js1304@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Johannes Weiner <hannes@cmpxchg.org>,
cgroups@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org,
Joonsoo Kim <iamjoonsoo.kim@lge.com>
Subject: Re: [PATCH] mm/memcontrol: fix NULL pointer dereference when use_hierarchy is 0
Date: Tue, 17 Feb 2015 09:33:27 +0100 [thread overview]
Message-ID: <20150217083327.GA32017@dhcp22.suse.cz> (raw)
In-Reply-To: <1424150699-5395-1-git-send-email-iamjoonsoo.kim@lge.com>
On Tue 17-02-15 14:24:59, Joonsoo Kim wrote:
> It can be possible to return NULL in parent_mem_cgroup()
> if use_hierarchy is 0.
This alone is not sufficient because the low limit is present only in
the unified hierarchy API and there is no use_hierarchy there. The
primary issue here is that the memcg has 0 usage so the previous
check for usage will not stop us. And that is bug IMO.
I think that the following patch would be more correct from semantic
POV:
---
next prev parent reply other threads:[~2015-02-17 8:33 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-17 5:24 Joonsoo Kim
2015-02-17 8:33 ` Michal Hocko [this message]
2015-02-17 12:28 ` Johannes Weiner
2015-02-25 1:20 ` Joonsoo Kim
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