From: Christian Brauner <christian@brauner.io>
To: Joel Fernandes <joel@joelfernandes.org>
Cc: jannh@google.com, khlebnikov@yandex-team.ru, luto@kernel.org,
dhowells@redhat.com, serge@hallyn.com, ebiederm@xmission.com,
linux-api@vger.kernel.org, linux-kernel@vger.kernel.org,
arnd@arndb.de, keescook@chromium.org, adobriyan@gmail.com,
tglx@linutronix.de, mtk.manpages@gmail.com, bl0pbl33p@gmail.com,
ldv@altlinux.org, akpm@linux-foundation.org, oleg@redhat.com,
nagarathnam.muthusamy@oracle.com, cyphar@cyphar.com,
viro@zeniv.linux.org.uk, dancol@google.com
Subject: Re: [PATCH v1 2/4] pid: add pidctl()
Date: Tue, 26 Mar 2019 18:17:03 +0100 [thread overview]
Message-ID: <20190326171702.smehtebw4e656ehl@brauner.io> (raw)
In-Reply-To: <20190326171525.GA116974@google.com>
On Tue, Mar 26, 2019 at 01:15:25PM -0400, Joel Fernandes wrote:
> On Tue, Mar 26, 2019 at 06:08:28PM +0100, Christian Brauner wrote:
> [snip]
> > > > + struct pid *struct_pid;
> > > > + pid_t result;
> > > > +
> > > > + if (flags)
> > > > + return -EINVAL;
> > > > +
> > > > + switch (cmd) {
> > > > + case PIDCMD_QUERY_PID:
> > > > + break;
> > > > + case PIDCMD_QUERY_PIDNS:
> > > > + if (pid)
> > > > + return -EINVAL;
> > > > + break;
> > > > + case PIDCMD_GET_PIDFD:
> > > > + break;
> > > > + default:
> > > > + return -EOPNOTSUPP;
> > > > + }
> > > > +
> > > > + source_ns = get_pid_ns_by_fd(source);
> > > > + if (IS_ERR(source_ns))
> > > > + return PTR_ERR(source_ns);
> > > > +
> > > > + target_ns = get_pid_ns_by_fd(target);
> > > > + if (IS_ERR(target_ns)) {
> > > > + put_pid_ns(source_ns);
> > > > + return PTR_ERR(target_ns);
> > > > + }
> > > > +
> > > > + if (cmd == PIDCMD_QUERY_PIDNS) {
> > > > + result = pidns_related(source_ns, target_ns);
> > > > + } else {
> > > > + rcu_read_lock();
> > > > + struct_pid = get_pid(find_pid_ns(pid, source_ns));
> > > > + rcu_read_unlock();
> > > > +
> > > > + if (struct_pid)
> > > > + result = pid_nr_ns(struct_pid, target_ns);
> > > > + else
> > > > + result = -ESRCH;
> > > > +
> > > > + if (cmd == PIDCMD_GET_PIDFD && (result > 0))
> > > > + result = pidfd_create_fd(struct_pid, O_CLOEXEC);
> > >
> > > pidfd_create_fd already does put_pid on errors..
> >
> > it also takes its own reference
> >
> > >
> > > > +
> > > > + if (!result)
> > > > + result = -ENOENT;
> > > > +
> > > > + put_pid(struct_pid);
> > >
> > > so on error you would put_pid twice which seems odd.. I would suggest, don't
> > > release the pid ref from within pidfd_create_fd, release the ref from the
> > > caller. Speaking of which, I added to my list to convert the pid->count to
> > > refcount_t at some point :)
> >
> > as i said, pidfd_create_fd takes its own reference
>
> Oh. That was easy to miss. Fair enough. I take that comment back.
>
> Please also reply to the other comments I posted, thanks. Generally on LKML,
> I have seen there is an expectation to reply to all reviewer's review
> comments even if you agree with them. This helps keep the review going
> smoothly. Just my 2 cents.
I tend to do it in multiple mails depending on whether or not I need to
think about a comment or not.
next prev parent reply other threads:[~2019-03-26 17:17 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-26 15:55 [PATCH v1 0/4] pid: add pidctl() Christian Brauner
2019-03-26 15:55 ` [PATCH v1 1/4] Make anon_inodes unconditional Christian Brauner
2019-03-26 15:55 ` [PATCH v1 2/4] pid: add pidctl() Christian Brauner
2019-03-26 16:17 ` Daniel Colascione
2019-03-26 16:23 ` Christian Brauner
2019-03-26 16:31 ` Christian Brauner
2019-03-26 16:34 ` Christian Brauner
2019-03-26 16:38 ` Daniel Colascione
2019-03-26 16:43 ` Christian Brauner
2019-03-26 16:50 ` Daniel Colascione
2019-03-26 17:05 ` Christian Brauner
2019-03-26 16:42 ` Andy Lutomirski
2019-03-26 16:46 ` Christian Brauner
2019-03-26 17:00 ` Daniel Colascione
2019-03-26 16:33 ` Daniel Colascione
2019-03-26 17:06 ` Joel Fernandes
2019-03-26 17:08 ` Christian Brauner
2019-03-26 17:15 ` Joel Fernandes
2019-03-26 17:17 ` Christian Brauner [this message]
2019-03-26 17:18 ` Joel Fernandes
2019-03-26 17:22 ` Christian Brauner
2019-03-26 18:10 ` Joel Fernandes
2019-03-26 18:19 ` Christian Brauner
2019-03-26 18:47 ` Joel Fernandes
2019-03-26 19:19 ` Christian Brauner
2019-03-26 19:51 ` Joel Fernandes
2019-03-26 19:57 ` Christian Brauner
2019-03-26 15:55 ` [PATCH v1 3/4] signal: support pidctl() with pidfd_send_signal() Christian Brauner
2019-03-26 15:55 ` [PATCH v1 4/4] tests: add pidctl() tests Christian Brauner
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