From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752061AbdIIWeP (ORCPT ); Sat, 9 Sep 2017 18:34:15 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:41776 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751975AbdIIWYx (ORCPT ); Sat, 9 Sep 2017 18:24:53 -0400 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "Vovo Yang" , "Eric W. Biederman" , "Guenter Roeck" Date: Sat, 09 Sep 2017 22:47:14 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 013/233] pid_ns: Sleep in TASK_INTERRUPTIBLE in zap_pid_ns_processes In-Reply-To: X-SA-Exim-Connect-IP: 2a02:8011:400e:2:6f00:88c8:c921:d332 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.48-rc1 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. Apparently under heavy load this has been allowing Chrome to trigger the hung time task timeout error and cause ChromeOS to reboot. Reported-by: Vovo Yang Reported-by: Guenter Roeck Tested-by: Guenter Roeck Fixes: 6347e9009104 ("pidns: guarantee that the pidns init will be the last pidns process reaped") Signed-off-by: "Eric W. Biederman" Signed-off-by: Ben Hutchings --- kernel/pid_namespace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/kernel/pid_namespace.c +++ b/kernel/pid_namespace.c @@ -234,7 +234,7 @@ void zap_pid_ns_processes(struct pid_nam * Make sure they all go away, see free_pid(). */ for (;;) { - set_current_state(TASK_UNINTERRUPTIBLE); + set_current_state(TASK_INTERRUPTIBLE); if (pid_ns->nr_hashed == init_pids) break; schedule();