From: Oleg Nesterov <oleg@redhat.com>
To: Christian Brauner <christian@brauner.io>
Cc: Joel Fernandes <joel@joelfernandes.org>,
Daniel Colascione <dancol@google.com>,
Jann Horn <jannh@google.com>, Florian Weimer <fweimer@redhat.com>,
kernel list <linux-kernel@vger.kernel.org>,
Andy Lutomirski <luto@amacapital.net>,
Steven Rostedt <rostedt@goodmis.org>,
Suren Baghdasaryan <surenb@google.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Alexey Dobriyan <adobriyan@gmail.com>,
Al Viro <viro@zeniv.linux.org.uk>,
Andrei Vagin <avagin@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
Arnd Bergmann <arnd@arndb.de>,
"Eric W. Biederman" <ebiederm@xmission.com>,
Kees Cook <keescook@chromium.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
"open list:KERNEL SELFTEST FRAMEWORK"
<linux-kselftest@vger.kernel.org>, Michal Hocko <mhocko@suse.com>,
Nadav Amit <namit@vmware.com>, Serge Hallyn <serge@hallyn.com>,
Shuah Khan <shuah@kernel.org>,
Stephen Rothwell <sfr@canb.auug.org.au>,
Taehee Yoo <ap420073@gmail.com>, Tejun Heo <tj@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
kernel-team <kernel-team@android.com>,
Tycho Andersen <tycho@tycho.ws>
Subject: Re: [PATCH RFC 1/2] Add polling support to pidfd
Date: Sat, 20 Apr 2019 13:51:26 +0200 [thread overview]
Message-ID: <20190420115125.GC17468@redhat.com> (raw)
In-Reply-To: <CAHrFyr6qqj-q9nSVuNhFL5WOcuQstAFvaDu2544OpeMe6jawQw@mail.gmail.com>
On 04/19, Christian Brauner wrote:
>
> > Just for the exit notification purposes, the states are:
> > if process has exit_state == 0, block.
> > if process is zombie/dead but not reaped, then return POLLIN
> > if process is reaped, then return POLLIN | POLLHUP
>
> Oleg was explicitly against EXIT_ZOMBIE/DEAD thing, no? He said so in a
> prior mail. Has this been addressed?
Yes, please don't use EXIT_XXX codes, nobody should ever use them except the
core kernel exit/wait paths. For example, EXIT_DEAD means that the task auto-
reaps or its parent had to temporary drop tasklist.
Just check ->exit_state != 0 && thread_group_empty(). Note that we need
thread_group_empty() only for the case when the task is traced, in this case
we have an extra notification for debugger which can confuse pidfd_poll().
And of course, everything will differ if/when we will need to monitor the
sub-threads.
And btw I don't think it needs tasklist_lock, but lets discuss this when we
have a new version based on pidfd.
Oleg.
next prev parent reply other threads:[~2019-04-20 11:51 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-11 17:50 [PATCH RFC 1/2] Add polling support to pidfd Joel Fernandes (Google)
2019-04-11 17:50 ` [PATCH RFC 2/2] Add selftests for pidfd polling Joel Fernandes (Google)
2019-04-12 14:51 ` Tycho Andersen
2019-04-11 20:00 ` [PATCH RFC 1/2] Add polling support to pidfd Joel Fernandes
2019-04-11 20:02 ` Christian Brauner
2019-04-11 20:20 ` Joel Fernandes
2019-04-12 21:32 ` Andy Lutomirski
2019-04-13 0:09 ` Joel Fernandes
[not found] ` <CAKOZuetX4jMPDtDqAvGgSNo4BHf9BOnu79ufEiULfM5X5nDyyQ@mail.gmail.com>
2019-04-13 0:56 ` Daniel Colascione
2019-04-14 18:19 ` Linus Torvalds
2019-04-16 12:04 ` Oleg Nesterov
2019-04-16 12:43 ` Oleg Nesterov
2019-04-16 19:20 ` Joel Fernandes
2019-04-16 19:32 ` Joel Fernandes
2019-04-17 13:09 ` Oleg Nesterov
2019-04-18 17:23 ` Jann Horn
2019-04-18 17:26 ` Christian Brauner
2019-04-18 17:53 ` Daniel Colascione
2019-04-19 19:02 ` Joel Fernandes
2019-04-19 19:18 ` Christian Brauner
2019-04-19 19:22 ` Christian Brauner
2019-04-19 19:42 ` Christian Brauner
2019-04-19 19:49 ` Joel Fernandes
2019-04-19 20:01 ` Christian Brauner
2019-04-19 21:13 ` Joel Fernandes
2019-04-19 20:34 ` Daniel Colascione
2019-04-19 20:57 ` Christian Brauner
2019-04-19 21:20 ` Joel Fernandes
2019-04-19 21:24 ` Daniel Colascione
2019-04-19 21:45 ` Joel Fernandes
2019-04-19 22:08 ` Daniel Colascione
2019-04-19 22:17 ` Christian Brauner
2019-04-19 22:37 ` Daniel Colascione
2019-04-24 8:04 ` Enrico Weigelt, metux IT consult
2019-04-19 21:59 ` Christian Brauner
2019-04-20 11:51 ` Oleg Nesterov [this message]
2019-04-20 12:26 ` Oleg Nesterov
2019-04-20 12:35 ` Christian Brauner
2019-04-19 23:11 ` Linus Torvalds
2019-04-19 23:20 ` Christian Brauner
2019-04-19 23:32 ` Linus Torvalds
2019-04-19 23:36 ` Daniel Colascione
2019-04-20 0:46 ` Joel Fernandes
2019-04-19 21:21 ` Daniel Colascione
2019-04-19 21:48 ` Christian Brauner
2019-04-19 22:02 ` Christian Brauner
2019-04-19 22:46 ` Daniel Colascione
2019-04-19 23:12 ` Christian Brauner
2019-04-19 23:46 ` Daniel Colascione
2019-04-20 0:17 ` Christian Brauner
2019-04-24 9:05 ` Enrico Weigelt, metux IT consult
2019-04-24 9:03 ` Enrico Weigelt, metux IT consult
2019-04-19 22:35 ` Daniel Colascione
2019-04-19 23:02 ` Christian Brauner
2019-04-19 23:29 ` Daniel Colascione
2019-04-20 0:02 ` Christian Brauner
2019-04-24 9:17 ` Enrico Weigelt, metux IT consult
2019-04-24 9:11 ` Enrico Weigelt, metux IT consult
2019-04-24 8:56 ` Enrico Weigelt, metux IT consult
2019-04-24 8:20 ` Enrico Weigelt, metux IT consult
2019-04-19 15:43 ` Oleg Nesterov
2019-04-19 18:12 ` Joel Fernandes
2019-04-18 18:44 ` Jonathan Kowalski
2019-04-18 18:57 ` Daniel Colascione
2019-04-18 19:14 ` Linus Torvalds
2019-04-19 19:05 ` Joel Fernandes
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