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Date:   Thu, 2 Jun 2022 11:41:32 -0700
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Roman Gushchin <roman.gushchin@linux.dev>
Cc:     linux-mm@kvack.org, Dave Chinner <dchinner@redhat.com>,
        linux-kernel@vger.kernel.org,
        Kent Overstreet <kent.overstreet@gmail.com>,
        Hillf Danton <hdanton@sina.com>,
        Christophe JAILLET <christophe.jaillet@wanadoo.fr>,
        Muchun Song <songmuchun@bytedance.com>
Subject: Re: [PATCH v5 6/6] mm: shrinkers: add scan interface for shrinker
 debugfs
Message-Id: <20220602114132.f6e5675b2d2a4085b9b1e8c4@linux-foundation.org>
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References: <20220601032227.4076670-1-roman.gushchin@linux.dev>
        <20220601032227.4076670-7-roman.gushchin@linux.dev>
        <20220601142351.5e04fea5586ca51898d8785f@linux-foundation.org>
        <YpgKttTowT22mKPQ@carbon>
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On Wed, 1 Jun 2022 17:56:22 -0700 Roman Gushchin <roman.gushchin@linux.dev> wrote:

> > 
> > > +	ssize_t ret;
> > > +
> > > +	if (copy_from_user(kbuf, buf, read_len))
> > > +		return -EFAULT;
> > > +	kbuf[read_len] = '\0';
> > > +
> > > +	if (sscanf(kbuf, "%lu %d %lu", &ino, &nid, &nr_to_scan) < 2)
> > 
> > Was it intentional to permit more than three args?
> 
> Good catch! No, of course it wasn't intentional.
> 
> Below is an updated version of this patch.
> 
> ...
>
> +	if (sscanf(kbuf, "%lu %d %lu", &ino, &nid, &nr_to_scan) != 2)
> +		return -EINVAL;

s/2/3/methinks?