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From: Oleg Nesterov <oleg@redhat.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Aleksa Sarai <asarai@suse.com>,
	Andy Lutomirski <luto@amacapital.net>,
	Attila Fazekas <afazekas@redhat.com>, Jann Horn <jann@thejh.net>,
	Kees Cook <keescook@chromium.org>,
	Michal Hocko <mhocko@kernel.org>,
	Ulrich Obergfell <uobergfe@redhat.com>,
	linux-kernel@vger.kernel.org, linux-api@vger.kernel.org
Subject: Re: [RFC][PATCH 2/2] exec: If possible don't wait for ptraced threads to be reaped
Date: Mon, 3 Apr 2017 20:12:52 +0200	[thread overview]
Message-ID: <20170403181252.GA31390@redhat.com> (raw)
In-Reply-To: <877f32k5ew.fsf@xmission.com>

On 04/02, Eric W. Biederman wrote:
>
> Oleg Nesterov <oleg@redhat.com> writes:
>
> > And btw zap_other_threads(may_hang == 0) is racy. Either you need tasklist or
> > exit_notify() should set tsk->exit_state under siglock, otherwise zap() can
> > return the wrong count.
>
> zap_other_thread(tsk, 0) only gets called in the case where we don't
> care about the return value.  It does not get called from fs/exec.c

I meant that may_hang == 0 implies zap_other_threads(do_count => -1) which should
return the number of threads which didn't pass exit_notify(). The returned value
can be wrong unless you change exit_notify() to set exit_state under siglock.

Oleg.

  reply	other threads:[~2017-04-03 18:13 UTC|newest]

Thread overview: 63+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-13 14:14 [PATCH 0/2] fix the traced mt-exec deadlock Oleg Nesterov
2017-02-13 14:15 ` [PATCH 1/2] exec: don't wait for zombie threads with cred_guard_mutex held Oleg Nesterov
2017-02-13 16:12   ` kbuild test robot
2017-02-13 16:47     ` Oleg Nesterov
2017-02-13 16:39   ` kbuild test robot
2017-02-13 17:27   ` Mika Penttilä
2017-02-13 18:01     ` Oleg Nesterov
2017-02-13 18:04   ` [PATCH V2 " Oleg Nesterov
2017-02-16 11:42     ` Eric W. Biederman
2017-02-20 15:22       ` Oleg Nesterov
2017-02-20 15:36         ` Oleg Nesterov
2017-02-20 22:30         ` Eric W. Biederman
2017-02-21 17:53           ` Oleg Nesterov
2017-02-21 20:20             ` Eric W. Biederman
2017-02-22 17:41               ` Oleg Nesterov
2017-02-17  4:42     ` Eric W. Biederman
2017-02-20 15:50       ` Oleg Nesterov
2017-02-13 14:15 ` [PATCH 2/2] ptrace: ensure PTRACE_EVENT_EXIT won't stop if the tracee is killed by exec Oleg Nesterov
2017-02-24 16:03 ` [PATCH 0/2] fix the traced mt-exec deadlock Oleg Nesterov
2017-03-03  1:05   ` Eric W. Biederman
2017-03-03 17:33     ` Oleg Nesterov
2017-03-03 18:23       ` Eric W. Biederman
2017-03-03 18:59         ` Eric W. Biederman
2017-03-03 20:06           ` Eric W. Biederman
2017-03-03 20:11             ` [RFC][PATCH] exec: Don't wait for ptraced threads to be reaped Eric W. Biederman
2017-03-04 17:03               ` Oleg Nesterov
2017-03-30  8:07                 ` Eric W. Biederman
2017-04-01  5:11                   ` [RFC][PATCH 0/2] exec: Fixing ptrace'd mulit-threaded hang Eric W. Biederman
2017-04-01  5:14                     ` [RFC][PATCH 1/2] sighand: Count each thread group once in sighand_struct Eric W. Biederman
2017-04-01  5:16                     ` [RFC][PATCH 2/2] exec: If possible don't wait for ptraced threads to be reaped Eric W. Biederman
2017-04-02 15:35                       ` Oleg Nesterov
2017-04-02 18:53                         ` Eric W. Biederman
2017-04-03 18:12                           ` Oleg Nesterov [this message]
2017-04-03 21:04                             ` Eric W. Biederman
2017-04-05 16:44                               ` Oleg Nesterov
2017-04-02 15:38                     ` [RFC][PATCH 0/2] exec: Fixing ptrace'd mulit-threaded hang Oleg Nesterov
2017-04-02 22:50                     ` [RFC][PATCH v2 0/5] " Eric W. Biederman
2017-04-02 22:51                       ` [RFC][PATCH v2 1/5] ptrace: Don't wait in PTRACE_O_TRACEEXIT for exec or coredump Eric W. Biederman
2017-04-05 16:19                         ` Oleg Nesterov
2017-04-02 22:51                       ` [RFC][PATCH v2 2/5] sighand: Count each thread group once in sighand_struct Eric W. Biederman
2017-04-02 22:52                       ` [RFC][PATCH v2 3/5] clone: Disallown CLONE_THREAD with a shared sighand_struct Eric W. Biederman
2017-04-05 16:24                         ` Oleg Nesterov
2017-04-05 17:34                           ` Eric W. Biederman
2017-04-05 18:11                             ` Oleg Nesterov
2017-04-02 22:53                       ` [RFC][PATCH v2 4/5] exec: If possible don't wait for ptraced threads to be reaped Eric W. Biederman
2017-04-05 16:15                         ` Oleg Nesterov
2017-04-02 22:57                       ` [RFC][PATCH v2 5/5] signal: Don't allow accessing signal_struct by old threads after exec Eric W. Biederman
2017-04-05 16:18                         ` Oleg Nesterov
2017-04-05 18:16                           ` Eric W. Biederman
2017-04-06 15:48                             ` Oleg Nesterov
2017-04-02 16:15                   ` [RFC][PATCH] exec: Don't wait for ptraced threads to be reaped Oleg Nesterov
2017-04-02 21:07                     ` Eric W. Biederman
2017-04-03 18:37                       ` Oleg Nesterov
2017-04-03 22:49                         ` Eric W. Biederman
2017-04-03 22:49                         ` scope of cred_guard_mutex Eric W. Biederman
2017-04-05 16:08                           ` Oleg Nesterov
2017-04-05 16:11                             ` Kees Cook
2017-04-05 17:53                             ` Eric W. Biederman
2017-04-05 18:15                               ` Oleg Nesterov
2017-04-06 15:55                           ` Oleg Nesterov
2017-04-07 22:07                             ` Kees Cook
2017-09-04  3:19                       ` [RFC][PATCH] exec: Don't wait for ptraced threads to be reaped Robert O'Callahan
2017-03-04 16:54         ` [PATCH 0/2] fix the traced mt-exec deadlock Oleg Nesterov

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