From: Christian Brauner <christian@brauner.io>
To: Oleg Nesterov <oleg@redhat.com>
Cc: torvalds@linux-foundation.org, viro@zeniv.linux.org.uk,
jannh@google.com, dhowells@redhat.com, linux-api@vger.kernel.org,
linux-kernel@vger.kernel.org, serge@hallyn.com, luto@kernel.org,
arnd@arndb.de, ebiederm@xmission.com, keescook@chromium.org,
tglx@linutronix.de, mtk.manpages@gmail.com,
akpm@linux-foundation.org, cyphar@cyphar.com,
joel@joelfernandes.org, dancol@google.com
Subject: Re: [PATCH v1 3/4] signal: support CLONE_PIDFD with pidfd_send_signal
Date: Wed, 17 Apr 2019 16:11:44 +0200 [thread overview]
Message-ID: <20190417141144.k2kmg7hd7pdpywyw@brauner.io> (raw)
In-Reply-To: <20190417140106.GG32622@redhat.com>
On Wed, Apr 17, 2019 at 04:01:06PM +0200, Oleg Nesterov wrote:
> On 04/16, Christian Brauner wrote:
> >
> > @@ -3581,12 +3588,12 @@ SYSCALL_DEFINE4(pidfd_send_signal, int, pidfd, int, sig,
> > if (flags)
> > return -EINVAL;
> >
> > - f = fdget_raw(pidfd);
> > + f = fdget(pidfd);
>
> could you explain this change?
>
> I am just curious, I don't understand why should we disallow O_PATH and how
> this connects to this patch.
Sending a signal through a pidfd is considered to be on a par with a
"write" to that pidfd.
Additionally, we use the fops associated with the fd to detect whether
it is actually a pidfd or not. This is not possible with O_PATH since
f_ops will be set to dummy fops. So we already correctly error out since
we detect that it is an O_PATH before fdget_raw(). This just takes the
opportunity to fix it.
Christian
next prev parent reply other threads:[~2019-04-17 14:11 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-16 17:02 [PATCH v1 0/4] clone: add CLONE_PIDFD Christian Brauner
2019-04-16 17:02 ` [PATCH v1 1/4] Make anon_inodes unconditional Christian Brauner
2019-04-16 17:02 ` [PATCH v1 2/4] clone: add CLONE_PIDFD Christian Brauner
2019-04-17 14:22 ` Oleg Nesterov
2019-04-17 14:25 ` Christian Brauner
2019-04-17 14:28 ` Christian Brauner
2019-04-18 9:36 ` Christian Brauner
2019-04-16 17:02 ` [PATCH v1 3/4] signal: support CLONE_PIDFD with pidfd_send_signal Christian Brauner
2019-04-17 14:01 ` Oleg Nesterov
2019-04-17 14:11 ` Christian Brauner [this message]
2019-04-17 15:20 ` Oleg Nesterov
2019-04-17 15:36 ` Christian Brauner
2019-04-16 17:02 ` [PATCH v1 4/4] samples: show race-free pidfd metadata access Christian Brauner
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