linux-kernel - Re: [PATCH 0/2] mm->owner to mm->memcg fixes

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Message-ID: <20180530115246.GB20910@dhcp22.suse.cz>
Date:   Wed, 30 May 2018 13:52:46 +0200
From:   Michal Hocko <mhocko@...nel.org>
To:     "Eric W. Biederman" <ebiederm@...ssion.com>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Johannes Weiner <hannes@...xchg.org>,
        Kirill Tkhai <ktkhai@...tuozzo.com>, peterz@...radead.org,
        viro@...iv.linux.org.uk, mingo@...nel.org,
        paulmck@...ux.vnet.ibm.com, keescook@...omium.org, riel@...hat.com,
        tglx@...utronix.de, kirill.shutemov@...ux.intel.com,
        marcos.souza.org@...il.com, hoeun.ryu@...il.com,
        pasha.tatashin@...cle.com, gs051095@...il.com, dhowells@...hat.com,
        rppt@...ux.vnet.ibm.com, linux-kernel@...r.kernel.org,
        Balbir Singh <balbir@...ux.vnet.ibm.com>,
        Tejun Heo <tj@...nel.org>, Oleg Nesterov <oleg@...hat.com>
Subject: Re: [PATCH 0/2] mm->owner to mm->memcg fixes

On Wed 23-05-18 14:46:43, Eric W. Biederman wrote:
[...]
> As two processes sharing an mm is useless and highly unlikely there is
> no need to handle this case well, it just needs to be handled well
> enough to prevent an indefinite loop.  So when css_tryget_online fails
> just treat the mm as belong to the root memory cgroup.

Does that mean that a malicious user can construct such a task and
runaway from its limits?

-- 
Michal Hocko
SUSE Labs