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Date:   Fri, 8 Jan 2021 17:50:08 -0800
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Michal Hocko <mhocko@suse.com>
Cc:     Kees Cook <keescook@chromium.org>,
        Xiaoming Ni <nixiaoming@huawei.com>,
        linux-kernel@vger.kernel.org, mcgrof@kernel.org,
        yzaikin@google.com, adobriyan@gmail.com,
        linux-fsdevel@vger.kernel.org, vbabka@suse.cz, wangle6@huawei.com
Subject: Re: [PATCH v2] proc_sysctl: fix oops caused by incorrect command
 parameters.
Message-Id: <20210108175008.da3c60a6e402f5f1ddab2a65@linux-foundation.org>
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On Fri, 8 Jan 2021 21:10:25 +0100 Michal Hocko <mhocko@suse.com> wrote:

> > > Why would that matter? A missing value is clearly a error path and it
> > > should be reported.
> > 
> > This test is in the correct place. I think it's just a question of the
> > return values.
> 
> I was probably not clear. The test for val is at the right place. I
> would just expect -EINVAL and have the generic code to report.

It does seem a bit screwy that process_sysctl_arg() returns zero in all
situations (parse_args() is set up to handle an error return from it). 
But this patch is consistent with all the other error handling in
process_sysctl_arg().