linux-kernel - Re: [PATCH 2/2] userns,pidns: Force thread group sharing, not signal handler sharing

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Message-ID: <20150812172418.GA6370@redhat.com>
Date:	Wed, 12 Aug 2015 19:24:18 +0200
From:	Oleg Nesterov <oleg@...hat.com>
To:	"Eric W. Biederman" <ebiederm@...ssion.com>
Cc:	"Kirill A. Shutemov" <kirill@...temov.name>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Kees Cook <keescook@...omium.org>,
	David Howells <dhowells@...hat.com>,
	linux-kernel@...r.kernel.org,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...nel.org>,
	"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
	Rik van Riel <riel@...hat.com>,
	Vladimir Davydov <vdavydov@...allels.com>,
	Ricky Zhou <rickyz@...omium.org>,
	Julien Tinnes <jln@...gle.com>
Subject: Re: [PATCH 2/2] userns,pidns: Force thread group sharing, not
	signal handler sharing

On 08/11, Eric W. Biederman wrote:
>
> The code that places signals in signal queues computes the uids, gids,
> and pids at the time the signals are enqueued.  Which means that tasks
> that share signal queues must be in the same pid and user namespaces.
>
> Sharing signal handlers is fine, but bizarre.
>
> So make the code in fork and userns_install clearer by only testing
> for what is functionally necessary.
>
> Also update the comment in unshare about unsharing a user namespace to
> be a little more explicit and make a little more sense.
>
> Signed-off-by: "Eric W. Biederman" <ebiederm@...ssion.com>

Acked-by: Oleg Nesterov <oleg@...hat.com>



But: Eric, Andrew, this means that

	user_ns-use-correct-check-for-single-threadedness.patch

in -mm tree should be dropped.

Oleg.

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