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Subject: Re: [PATCH v4 5/6] ipc: Clamp semmni to the real IPCMNI limit
To:     "Luis R. Rodriguez" <mcgrof@kernel.org>
Cc:     Kees Cook <keescook@chromium.org>, linux-kernel@vger.kernel.org,
        linux-fsdevel@vger.kernel.org,
        Andrew Morton <akpm@linux-foundation.org>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Matthew Wilcox <willy@infradead.org>
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 <20180312205235.GB4449@wotan.suse.de>
From:   Waiman Long <longman@redhat.com>
Organization: Red Hat
Message-ID: <1a506f57-a91b-aae9-7756-03268b6447f7@redhat.com>
Date:   Mon, 12 Mar 2018 16:59:59 -0400
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On 03/12/2018 04:52 PM, Luis R. Rodriguez wrote:
> On Mon, Mar 12, 2018 at 04:15:43PM -0400, Waiman Long wrote:
>> +	if (clamped)
>> +		pr_warn_once("sysctl: \"sem[3]\" was set out of range [%d, %d], clamped to %d.\n",
>> +			     0, IPCMNI, ns->sc_semmni);
> Why warn if the kernel already does that? If we can avoid more code on
> drivers the better.
>
>   Luis

As said before, this case is special because "sem" is a collection of 4
different values. The last one is semmni which I tries to apply the same
range clamping here, whereas the other 3 are left as they are. The
standard proc_dointvec_minmax() handler cannot be used here because of
that. I will clarify that in the commit log.

Cheers,
Longman