Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Mon, 22 Jun 2020 13:31:42 +0200
From:   Oleg Nesterov <oleg@redhat.com>
To:     Dominique Martinet <asmadeus@codewreck.org>
Cc:     Christian Brauner <christian.brauner@ubuntu.com>,
        Alexander Kapshuk <alexander.kapshuk@gmail.com>,
        linux-kernel@vger.kernel.org, ebiederm@xmission.com,
        akpm@linux-foundation.org, liuzhiqiang26@huawei.com,
        joel@joelfernandes.org, paulmck@linux.vnet.ibm.com,
        kernel test robot <lkp@intel.com>
Subject: Re: [PATCH] kernel/signal.c: Export symbol __lock_task_sighand
Message-ID: <20200622113141.GC6516@redhat.com>
References: <20200621133704.77896-1-alexander.kapshuk@gmail.com>
 <20200622062527.GA6516@redhat.com>
 <20200622083905.c3nurmkbo5yhd6lj@wittgenstein>
 <20200622102401.GA12377@nautica>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20200622102401.GA12377@nautica>
User-Agent: Mutt/1.5.24 (2015-08-30)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On 06/22, Dominique Martinet wrote:
>
> What about the possibility of sighand being null that the function does
> check, is that impossible for current as well?

It is only possible if "current" has already exited and passed exit_notify(),
iow if it is already a zombie and can be (auto)reaped.

Oleg.