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Date:   Tue, 8 Feb 2022 16:15:05 +0100
From:   Michal Hocko <mhocko@suse.com>
To:     Waiman Long <longman@redhat.com>
Cc:     Johannes Weiner <hannes@cmpxchg.org>,
        Vladimir Davydov <vdavydov.dev@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Petr Mladek <pmladek@suse.com>,
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        Sergey Senozhatsky <senozhatsky@chromium.org>,
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        Mike Rapoport <rppt@kernel.org>,
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        Roman Gushchin <guro@fb.com>,
        Rafael Aquini <aquini@redhat.com>,
        Mike Rapoport <rppt@linux.ibm.com>
Subject: Re: [PATCH v5 3/4] mm/page_owner: Print memcg information
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On Tue 08-02-22 13:13:15, Michal Hocko wrote:
> On Mon 07-02-22 19:05:31, Waiman Long wrote:
[...]
> > +	ret += scnprintf(kbuf + ret, count - ret, "\n");
> 
> I do not see any overflow prevention here. I believe you really need to
> check ret >= count after each scnprintf/cgroup_name.

OK, I have only now realized that scnprintf would return size - 1 on
overflow so explicitly checking for the overlow shouldn't be reallu
necessary.
-- 
Michal Hocko
SUSE Labs