From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 04ACC19CD1D for ; Mon, 21 Apr 2025 16:17:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745252252; cv=none; b=LSS2zUhhGBzDcXCtuWB0Q9KFgC19+zwv7pPkgdRJVKorMxjrDEoSggMciQ3JNLePjl88Fl5/z6uRUGzbHpQ2hlmjSgqMbFw9/1zAjBgADb8c/ka/ZMdRbN7zIjiUkBdMUemBhnB3F/3hwltaZ6v72Zb5sdpgjxR8FjmaxdzEm8Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745252252; c=relaxed/simple; bh=1Mxdzu3Dy35vNGbmZ1vQdpiZUkKpIxDbzfQOEgcte8Q=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=O/YWUBAs25r/cL8jJgORbcd2i7yGzWwE6xbwvDENkvW6iYJuQlNcvLRgMEY9isoxchZhbKWY6f6ohS/zQIa4Q69cjrWeYmyA41DnmbENcyiYjsoPBL3XQ80X5fRGLDhIwgFBhS0Gqvjm+vPKUSExOcf3PyTlxuNuORt4wm9A5uU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=Ex8v9B/U; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Ex8v9B/U" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1745252249; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=AxyLW5sq+o6vn0oRNHNlsA+8mL41449UYQjhSR/iYXk=; b=Ex8v9B/UGzNppCN3aPA6+7FekSUkSOVp0QPSXo72czsrxbFgNp0qqe6r+QyvXcU9GC0xgu dZB5etw3Tdu+HNaPYnrMLMOXT6oxh0CwYaamIqcim191IG4uBcryNNLXSVS0VQNJIqcryK ofSThoKQC5wIa4pn2mY0RzWUbE9nmZE= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-647-xSX_DSPfMgS-vDxGLqpAcA-1; Mon, 21 Apr 2025 12:17:28 -0400 X-MC-Unique: xSX_DSPfMgS-vDxGLqpAcA-1 X-Mimecast-MFC-AGG-ID: xSX_DSPfMgS-vDxGLqpAcA_1745252247 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 0C0191956088; Mon, 21 Apr 2025 16:17:27 +0000 (UTC) Received: from fedora.redhat.com (unknown [10.22.65.113]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 0AFC430001A2; Mon, 21 Apr 2025 16:17:25 +0000 (UTC) From: Joel Savitz To: linux-kernel@vger.kernel.org Cc: Joel Savitz , Jonathan Corbet , linux-doc@vger.kernel.org Subject: [PATCH v3] docs: namespace: Tweak and reword resource control doc Date: Mon, 21 Apr 2025 12:17:23 -0400 Message-ID: <20250421161723.1138903-1-jsavitz@redhat.com> Precedence: bulk X-Mailing-List: linux-doc@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Fix the document title and reword the phrasing to active voice. Signed-off-by: Joel Savitz --- Changes since v2: - Fix another typo Changes since v1: - Fix spelling of resource .../namespaces/resource-control.rst | 24 +++++++++---------- 1 file changed, 12 insertions(+), 12 deletions(-) diff --git a/Documentation/admin-guide/namespaces/resource-control.rst b/Documentation/admin-guide/namespaces/resource-control.rst index 369556e00f0c..553a44803231 100644 --- a/Documentation/admin-guide/namespaces/resource-control.rst +++ b/Documentation/admin-guide/namespaces/resource-control.rst @@ -1,17 +1,17 @@ -=========================== -Namespaces research control -=========================== +==================================== +User namespaces and resource control +==================================== -There are a lot of kinds of objects in the kernel that don't have -individual limits or that have limits that are ineffective when a set -of processes is allowed to switch user ids. With user namespaces -enabled in a kernel for people who don't trust their users or their -users programs to play nice this problems becomes more acute. +The kernel contains many kinds of objects that either don't have +individual limits or that have limits which are ineffective when +a set of processes is allowed to switch their UID. On a system +where the admins don't trust their users or their users' programs, +user namespaces expose the system to potential misuse of resources. -Therefore it is recommended that memory control groups be enabled in -kernels that enable user namespaces, and it is further recommended -that userspace configure memory control groups to limit how much -memory user's they don't trust to play nice can use. +In order to mitigate this, we recommend that admins enable memory +control groups on any system that enables user namespaces. +Furthermore, we recommend that admins configure the memory control +groups to limit the maximum memory usable by any untrusted user. Memory control groups can be configured by installing the libcgroup package present on most distros editing /etc/cgrules.conf, -- 2.45.2