Received-SPF: pass (google.com: domain of linux-kernel+bounces-56321-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:45d1:ec00::1 as permitted sender) client-ip=2604:1380:45d1:ec00::1;
Date: Wed, 7 Feb 2024 11:28:50 +0100
From: Oleg Nesterov <oleg@redhat.com>
To: Christian Brauner <brauner@kernel.org>
Cc: Tycho Andersen <tycho@tycho.pizza>,
	"Eric W . Biederman" <ebiederm@xmission.com>,
	linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
	Tycho Andersen <tandersen@netflix.com>
Subject: Re: [PATCH] pidfd: getfd should always report ESRCH if a task is
 exiting
Message-ID: <20240207102849.GA6627@redhat.com>
References: <20240206164308.62620-1-tycho@tycho.pizza>
 <20240206173722.GA3593@redhat.com>
 <20240206180607.GB3593@redhat.com>
 <ZcJ13uLxD6rTqqZZ@tycho.pizza>
 <20240206192553.GC3593@redhat.com>
 <20240207-beseitigen-ausfliegen-b2b95de67c4f@brauner>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20240207-beseitigen-ausfliegen-b2b95de67c4f@brauner>
User-Agent: Mutt/1.5.24 (2015-08-30)

On 02/07, Christian Brauner wrote:
>
> On Tue, Feb 06, 2024 at 08:25:54PM +0100, Oleg Nesterov wrote:
> > On 02/06, Tycho Andersen wrote:
> >
> > > On Tue, Feb 06, 2024 at 07:06:07PM +0100, Oleg Nesterov wrote:
> > > > Or we can check task->files != NULL rather than PF_EXITING.
> > > >
> > > > To me this looks even better, but looks more confusing without a comment.
> > > > OTOH, imo this needs a comment anyway ;)
> > >
> > > I thought about this, but I didn't really understand the null check in
> > > exit_files();
> >
> > I guess task->files can be NULL at least if it was cloned with
> > kernel_clone_args->no_files == T
>
> Won't this give false positives for vhost workers which do set
> ->no_files but are user workers? IOW, return -ESRCH even though -EBADF
> would be correct in this scenario?

OK, agreed. Lets check PF_EXITING or exit_state.

Oleg.