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Date: Thu, 13 Aug 2015 14:57:04 +0200
From: Oleg Nesterov <oleg@redhat.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>,
        Andrew Morton <akpm@linux-foundation.org>,
        Kees Cook <keescook@chromium.org>, David Howells <dhowells@redhat.com>,
        linux-kernel@vger.kernel.org, Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@kernel.org>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Rik van Riel <riel@redhat.com>,
        Vladimir Davydov <vdavydov@parallels.com>,
        Ricky Zhou <rickyz@chromium.org>, Julien Tinnes <jln@google.com>
Subject: Re: [PATCH v2] unshare: Unsharing a thread does not require
	unsharing a vm
Message-ID: <20150813125704.GB13984@redhat.com>
References: <20150728221111.GA23391@node.dhcp.inet.fi> <20150805172356.GA20490@redhat.com> <87wpx9sjhq.fsf@x220.int.ebiederm.org> <87614tr2jd.fsf@x220.int.ebiederm.org> <20150806130629.GA4728@redhat.com> <20150806134426.GA6843@redhat.com> <871tf9cnbi.fsf_-_@x220.int.ebiederm.org> <87vbclb8op.fsf_-_@x220.int.ebiederm.org> <20150812174847.GA6703@redhat.com> <87wpx046s6.fsf_-_@x220.int.ebiederm.org>
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On 08/12, Eric W. Biederman wrote:
>
> +	if (unshare_flags & (CLONE_SIGHAND | CLONE_VM)) {
> +		if (atomic_read(&current->sighand->count) > 1)
> +			return -EINVAL;
> +	}

I am still not sure we want this... please the the previous email.

But perhaps I missed something.

Oleg.