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From: "Robert O'Callahan" <robert-7ok7fSEJICeEi8DpZVb4nw@public.gmane.org>
To: "Eric W. Biederman" <ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
Cc: Oleg Nesterov <oleg-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	Andrew Morton
	<akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
	Aleksa Sarai <asarai-IBi9RG/b67k@public.gmane.org>,
	Andy Lutomirski <luto-kltTT9wpgjJwATOyAt5JVQ@public.gmane.org>,
	Attila Fazekas <afazekas-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	Jann Horn <jann-XZ1E9jl8jIdeoWH0uzbU5w@public.gmane.org>,
	Kees Cook <keescook-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
	Michal Hocko <mhocko-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
	Ulrich Obergfell
	<uobergfe-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
	open list <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [RFC][PATCH] exec: Don't wait for ptraced threads to be reaped.
Date: Mon, 4 Sep 2017 15:19:13 +1200	[thread overview]
Message-ID: <CAOp6jLbpfeypOqJO2B4D0Ye6AK0Ht6uh8GFX++j_kqMLFg21fw@mail.gmail.com> (raw)
In-Reply-To: <87inmmbjsq.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>

Sorry about replying to this old thread, but...

On Mon, Apr 3, 2017 at 9:07 AM, Eric W. Biederman <ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org> wrote:
> I don't know who actually useses PTRACE_O_TRACEEXIT so I don't actually
> know what the implications of changing it are.  Let's see...
>
> gdb - no
> upstart - no
> lldb - yes
> strace - no

For the record, rr uses PTRACE_O_TRACEEXIT.

When a thread exits we need to examine its address space to find its
robust futex list and record the changes that will be performed by the
kernel as it cleans up that list. So, any failures to deliver
PTRACE_EVENT_EXIT are potentially problematic for us because we won't
get a chance to examine the address space before it disappears.

Rob
-- 
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selthor  stor  edna  siewaoeodm  or v sstvr  esBa  kbvted,t rdsme,aoreseoouoto
o l euetiuruewFa  kbn e hnystoivateweh uresyf tulsa rehr  rdm  or rnea lurpr
.a war hsrer holsa rodvted,t  nenh hneireseoouot.tniesiewaoeivatewt sstvr  esn

  parent reply	other threads:[~2017-09-04  3:19 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20170213141452.GA30203@redhat.com>
     [not found] ` <20170224160354.GA845@redhat.com>
     [not found]   ` <87shmv6ufl.fsf@xmission.com>
     [not found]     ` <20170303173326.GA17899@redhat.com>
     [not found]       ` <20170303173326.GA17899-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2017-03-03 18:23         ` [PATCH 0/2] fix the traced mt-exec deadlock Eric W. Biederman
2017-03-03 18:59           ` Eric W. Biederman
     [not found]             ` <87d1dyw5iw.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2017-03-03 20:06               ` Eric W. Biederman
     [not found]                 ` <87tw7aunuh.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
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
     [not found]                         ` <8760ir192p.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2017-04-01  5:11                           ` [RFC][PATCH 0/2] exec: Fixing ptrace'd mulit-threaded hang Eric W. Biederman
     [not found]                             ` <878tnkpv8h.fsf_-_-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
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
     [not found]                                 ` <87vaqooggs.fsf_-_-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2017-04-02 15:35                                   ` Oleg Nesterov
     [not found]                                     ` <20170402153517.GA12637-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2017-04-02 18:53                                       ` Eric W. Biederman
     [not found]                                         ` <877f32k5ew.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2017-04-03 18:12                                           ` Oleg Nesterov
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
     [not found]                                 ` <874ly6a0h1.fsf_-_-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
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
     [not found]                                     ` <87k2728lrp.fsf_-_-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
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
     [not found]                                     ` <87zify76z9.fsf_-_-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2017-04-05 16:18                                       ` Oleg Nesterov
     [not found]                                         ` <20170405161812.GD14536-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2017-04-05 18:16                                           ` Eric W. Biederman
     [not found]                                             ` <87zifu90to.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
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
     [not found]                             ` <20170402161518.GC12637-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2017-04-02 21:07                               ` Eric W. Biederman
     [not found]                                 ` <87inmmbjsq.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2017-04-03 18:37                                   ` Oleg Nesterov
     [not found]                                     ` <20170403183728.GB31390-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
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
     [not found]                                         ` <87fuhpjeco.fsf_-_-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2017-04-06 15:55                                           ` Oleg Nesterov
     [not found]                                             ` <20170406155540.GC7444-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2017-04-07 22:07                                               ` Kees Cook
2017-09-04  3:19                                   ` Robert O'Callahan [this message]
     [not found]           ` <87tw7axlr0.fsf-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
2017-03-04 16:54             ` [PATCH 0/2] fix the traced mt-exec deadlock Oleg Nesterov

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