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From: ebiederm@xmission.com (Eric W. Biederman)
To: Guenter Roeck <linux@roeck-us.net>
Cc: Vovo Yang <vovoy@google.com>, Ingo Molnar <mingo@kernel.org>,
	linux-kernel@vger.kernel.org
Subject: Re: Threads stuck in zap_pid_ns_processes()
Date: Thu, 01 Jun 2017 12:08:58 -0500	[thread overview]
Message-ID: <87inkfab4l.fsf@xmission.com> (raw)
In-Reply-To: <e7826335-3cb5-a4bf-f382-252f8f0a94a4@roeck-us.net> (Guenter Roeck's message of "Sat, 13 May 2017 07:34:13 -0700")

Guenter Roeck <linux@roeck-us.net> writes:
>
> I think you nailed it. If I drop CLONE_NEWPID from the reproducer I get
> a zombie process.
>
> I guess the only question left is if zap_pid_ns_processes() should (or could)
> somehow detect that situation and return instead of waiting forever.
> What do you think ?

Any chance you can point me at the chromium code that is performing the
ptrace?

I want to conduct a review of the kernel semantics to see if the current
semantics make it unnecessarily easy to get into hang situations.  If
the semantics make it really easy to get into a hang situation I want
to see if there is anything we can do to delicately change the semantics
to avoid the hangs without breaking existing userspace.

We have a real problem in exec which has similar semantics and as long
as I am looking at one I figure I should look at the other.

Eric

  parent reply	other threads:[~2017-06-01 17:15 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-11 17:11 Threads stuck in zap_pid_ns_processes() Guenter Roeck
2017-05-11 17:31 ` Eric W. Biederman
2017-05-11 18:35   ` Guenter Roeck
2017-05-11 20:23     ` Eric W. Biederman
2017-05-11 20:48       ` Guenter Roeck
2017-05-11 21:39         ` Eric W. Biederman
2017-05-11 20:21   ` Guenter Roeck
2017-05-11 21:25     ` Eric W. Biederman
2017-05-11 22:47       ` Guenter Roeck
2017-05-11 23:19         ` Eric W. Biederman
2017-05-12  9:30           ` Vovo Yang
2017-05-12 13:26             ` Eric W. Biederman
2017-05-12 16:52               ` Guenter Roeck
2017-05-12 17:33                 ` Eric W. Biederman
2017-05-12 17:55                   ` [REVIEW][PATCH] pid_ns: Sleep in TASK_INTERRUPTIBLE in zap_pid_ns_processes Eric W. Biederman
2017-05-12 19:33                     ` Guenter Roeck
2017-05-12 19:43                   ` Threads stuck in zap_pid_ns_processes() Guenter Roeck
2017-05-12 20:03                     ` Eric W. Biederman
2017-05-13 14:34                       ` Guenter Roeck
2017-05-13 18:21                         ` Eric W. Biederman
2017-06-01 17:08                         ` Eric W. Biederman [this message]
2017-06-01 18:45                           ` Guenter Roeck
2017-06-01 19:36                             ` Eric W. Biederman
2017-06-01 21:43                               ` Guenter Roeck
2017-06-02  1:06                                 ` Eric W. Biederman
2017-05-12  3:42         ` Eric W. Biederman

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