From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751138AbdFALzr (ORCPT ); Thu, 1 Jun 2017 07:55:47 -0400 Received: from imap0.codethink.co.uk ([185.43.218.159]:33113 "EHLO imap0.codethink.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751060AbdFALzq (ORCPT ); Thu, 1 Jun 2017 07:55:46 -0400 Message-ID: <1496318134.2790.18.camel@codethink.co.uk> Subject: Re: [PATCH 4.4 040/103] pid_ns: Sleep in TASK_INTERRUPTIBLE in zap_pid_ns_processes From: Ben Hutchings To: "Eric W. Biederman" Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org, Vovo Yang , Guenter Roeck , Greg Kroah-Hartman Date: Thu, 01 Jun 2017 12:55:34 +0100 In-Reply-To: <20170523200900.480278614@linuxfoundation.org> References: <20170523200856.903752266@linuxfoundation.org> <20170523200900.480278614@linuxfoundation.org> Organization: Codethink Ltd. Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.12.9-1+b1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2017-05-23 at 22:09 +0200, Greg Kroah-Hartman wrote: > 4.4-stable review patch. If anyone has any objections, please let me know. > > ------------------ > > From: Eric W. Biederman > > commit b9a985db98961ae1ba0be169f19df1c567e4ffe0 upstream. > > The code can potentially sleep for an indefinite amount of time in > zap_pid_ns_processes triggering the hung task timeout, and increasing > the system average. This is undesirable. Sleep with a task state of > TASK_INTERRUPTIBLE instead of TASK_UNINTERRUPTIBLE to remove these > undesirable side effects. [...] This seems to rely on the task not actually being signallable due to the PF_EXITING flag. Using TASK_IDLE would be clearer (though less backport-able). Ben. -- Ben Hutchings Software Developer, Codethink Ltd.