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Date: Wed, 7 Feb 2024 10:11:54 +0100
From: Christian Brauner <brauner@kernel.org>
To: Oleg Nesterov <oleg@redhat.com>
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: <20240207-beseitigen-ausfliegen-b2b95de67c4f@brauner>
References: <20240206164308.62620-1-tycho@tycho.pizza>
 <20240206173722.GA3593@redhat.com>
 <20240206180607.GB3593@redhat.com>
 <ZcJ13uLxD6rTqqZZ@tycho.pizza>
 <20240206192553.GC3593@redhat.com>
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In-Reply-To: <20240206192553.GC3593@redhat.com>

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?