linux-kernel - Re: [PATCH 1/4] pidfd: support PIDFD_NONBLOCK in pidfd

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <20200901165315.GD4386@redhat.com>
Date:   Tue, 1 Sep 2020 18:53:16 +0200
From:   Oleg Nesterov <oleg@...hat.com>
To:     Christian Brauner <christian.brauner@...ntu.com>
Cc:     linux-kernel@...r.kernel.org,
        Christian Brauner <christian@...uner.io>,
        "Peter Zijlstra (Intel)" <peterz@...radead.org>,
        Ingo Molnar <mingo@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        "Eric W. Biederman" <ebiederm@...ssion.com>,
        Kees Cook <keescook@...omium.org>,
        Sargun Dhillon <sargun@...gun.me>,
        Aleksa Sarai <cyphar@...har.com>,
        linux-kselftest@...r.kernel.org,
        Josh Triplett <josh@...htriplett.org>,
        Jens Axboe <axboe@...nel.dk>, linux-api@...r.kernel.org
Subject: Re: [PATCH 1/4] pidfd: support PIDFD_NONBLOCK in pidfd_open()

On 09/01, Christian Brauner wrote:
>
> On Tue, Sep 01, 2020 at 06:23:10PM +0200, Oleg Nesterov wrote:
> > On 08/31, Christian Brauner wrote:
> > >
> > > --- /dev/null
> > > +++ b/include/uapi/linux/pidfd.h
> > > @@ -0,0 +1,12 @@
> > > +/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
> > > +
> > > +#ifndef _UAPI_LINUX_PIDFD_H
> > > +#define _UAPI_LINUX_PIDFD_H
> > > +
> > > +#include <linux/types.h>
> > > +#include <linux/fcntl.h>
> > > +
> > > +/* Flags for pidfd_open().  */
> > > +#define PIDFD_NONBLOCK O_NONBLOCK
> > > +
> > > +#endif /* _UAPI_LINUX_PIDFD_H */
> >
> > Why? Can't we simply use O_NONBLOCK ?
>
> It's the same thing we seem to do for any other (anon inode) fds:
>
> include/linux/eventfd.h:#define		EFD_NONBLOCK O_NONBLOCK
> include/uapi/linux/inotify.h:#define	IN_NONBLOCK O_NONBLOCK
> include/uapi/linux/signalfd.h:#define	SFD_NONBLOCK O_NONBLOCK
> include/uapi/linux/timerfd.h:#define	TFD_NONBLOCK O_NONBLOCK
>
> also for O_CLOEXEC:
>
> include/linux/eventfd.h:#define		EFD_CLOEXEC O_CLOEXEC
> include/linux/userfaultfd_k.h:#define	UFFD_CLOEXEC O_CLOEXEC
> include/uapi/linux/eventpoll.h:#define	EPOLL_CLOEXEC O_CLOEXEC
> include/uapi/linux/mount.h:#define	OPEN_TREE_CLOEXEC    O_CLOEXEC
> include/uapi/linux/perf_event.h:#define PERF_FLAG_FD_CLOEXEC (1UL << 3) /* O_CLOEXEC */
> include/uapi/linux/signalfd.h:#define	SFD_CLOEXEC O_CLOEXEC
> include/uapi/linux/timerfd.h:#define	TFD_CLOEXEC O_CLOEXEC
>
> So I think we should just do the same.

Hmm, OK, then I have to agree.

> A clean flag namespace seems
> nicer to me too tbh.

Disagree but this doesn't matter ;)

Oleg.