Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Fri, 2 Aug 2019 15:46:11 +0200
From:   Oleg Nesterov <oleg@redhat.com>
To:     Adrian Reber <areber@redhat.com>
Cc:     Christian Brauner <christian@brauner.io>,
        Eric Biederman <ebiederm@xmission.com>,
        Pavel Emelianov <xemul@virtuozzo.com>,
        Jann Horn <jannh@google.com>,
        Dmitry Safonov <0x7f454c46@gmail.com>,
        linux-kernel@vger.kernel.org, Andrei Vagin <avagin@gmail.com>,
        Mike Rapoport <rppt@linux.ibm.com>,
        Radostin Stoyanov <rstoyanov1@gmail.com>
Subject: Re: [PATCH v2 1/2] fork: extend clone3() to support CLONE_SET_TID
Message-ID: <20190802134611.GF20111@redhat.com>
References: <20190731161223.2928-1-areber@redhat.com>
 <20190731174135.GA30225@redhat.com>
 <20190802072511.GD18263@dcbz.redhat.com>
 <20190802124738.GC20111@redhat.com>
 <20190802132419.GD20111@redhat.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20190802132419.GD20111@redhat.com>
User-Agent: Mutt/1.5.24 (2015-08-30)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 08/02, Oleg Nesterov wrote:
>
> So Adrian, sorry for confusion, I think your patch is fine.

Yes... but do we really need the new CLONE_SET_TID ?

set_tid == 0 has no effect, can't we simply check kargs->set_tid != 0
before ns_capable() ?

and to remind, I still think alloc_pid() should use idr_is_empty(), but
I won't insist.

Oleg.