From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:56812 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751517AbcHBHGs (ORCPT ); Tue, 2 Aug 2016 03:06:48 -0400 Subject: Patch "kernel/sysrq, watchdog, sched/core: Reset watchdog on all CPUs while processing sysrq-w" has been added to the 4.4-stable tree To: aryabinin@virtuozzo.com, gregkh@linuxfoundation.org, mingo@kernel.org, peterz@infradead.org, tglx@linutronix.de, torvalds@linux-foundation.org Cc: , From: Date: Tue, 02 Aug 2016 09:03:54 +0200 Message-ID: <147012143423795@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled kernel/sysrq, watchdog, sched/core: Reset watchdog on all CPUs while processing sysrq-w to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: kernel-sysrq-watchdog-sched-core-reset-watchdog-on-all-cpus-while-processing-sysrq-w.patch and it can be found in the queue-4.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>From 57675cb976eff977aefb428e68e4e0236d48a9ff Mon Sep 17 00:00:00 2001 From: Andrey Ryabinin Date: Thu, 9 Jun 2016 15:20:05 +0300 Subject: kernel/sysrq, watchdog, sched/core: Reset watchdog on all CPUs while processing sysrq-w From: Andrey Ryabinin commit 57675cb976eff977aefb428e68e4e0236d48a9ff upstream. Lengthy output of sysrq-w may take a lot of time on slow serial console. Currently we reset NMI-watchdog on the current CPU to avoid spurious lockup messages. Sometimes this doesn't work since softlockup watchdog might trigger on another CPU which is waiting for an IPI to proceed. We reset softlockup watchdogs on all CPUs, but we do this only after listing all tasks, and this may be too late on a busy system. So, reset watchdogs CPUs earlier, in for_each_process_thread() loop. Signed-off-by: Andrey Ryabinin Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/1465474805-14641-1-git-send-email-aryabinin@virtuozzo.com Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- kernel/sched/core.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -4951,14 +4951,16 @@ void show_state_filter(unsigned long sta /* * reset the NMI-timeout, listing all files on a slow * console might take a lot of time: + * Also, reset softlockup watchdogs on all CPUs, because + * another CPU might be blocked waiting for us to process + * an IPI. */ touch_nmi_watchdog(); + touch_all_softlockup_watchdogs(); if (!state_filter || (p->state & state_filter)) sched_show_task(p); } - touch_all_softlockup_watchdogs(); - #ifdef CONFIG_SCHED_DEBUG sysrq_sched_debug_show(); #endif Patches currently in stable-queue which might be from aryabinin@virtuozzo.com are queue-4.4/vmlinux.lds-account-for-destructor-sections.patch queue-4.4/kernel-sysrq-watchdog-sched-core-reset-watchdog-on-all-cpus-while-processing-sysrq-w.patch