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From: Peter Zijlstra <peterz@infradead.org>
To: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Ingo Molnar <mingo@kernel.org>,
	Byungchul Park <byungchul.park@lge.com>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	Luca Abeni <luca.abeni@unitn.it>, Rik van Riel <riel@redhat.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	Wanpeng Li <wanpeng.li@hotmail.com>,
	Yuyang Du <yuyang.du@intel.com>, Petr Mladek <pmladek@suse.com>,
	Jan Kara <jack@suse.cz>,
	Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>,
	linux-kernel@vger.kernel.org,
	Mel Gorman <mgorman@techsingularity.net>,
	Mike Galbraith <umgwanakikbuti@gmail.com>
Subject: Re: [PATCH v2 1/7] sched/fair: Update the rq clock before detaching tasks
Date: Mon, 3 Oct 2016 16:42:46 +0200	[thread overview]
Message-ID: <20161003144246.GD3117@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <20161003143745.GG16071@codeblueprint.co.uk>

On Mon, Oct 03, 2016 at 03:37:45PM +0100, Matt Fleming wrote:
> On Mon, 03 Oct, at 02:49:07PM, Peter Zijlstra wrote:

> > The other is through switched_from() where its far harder (but still
> > possible afaict) to miss the update.
>  
> It was the former callchain.

Yep, just found it ;-)

I seem to hit a few you didn't as well.. let me prod at this a wee bit
more before I add more asserts..


4WARNING: CPU: 0 PID: 1 at ../kernel/sched/sched.h:797 detach_task_cfs_rq+0x6fe/0x930
rq->clock_update_flags < RQCF_ACT_SKIPdModules linked in:
dCPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.8.0-00637-g67223e2-dirty #553
dHardware name: Intel Corporation S2600GZ/S2600GZ, BIOS SE5C600.86B.02.02.0002.122320131210 12/23/2013
 ffffc900000cbc00 ffffffff816152c5 ffffc900000cbc50 0000000000000000
 ffffc900000cbc40 ffffffff810d5bab 0000031d00017b00 ffff88042f817b68
 ffff88042dbb0000 ffff88042f817b00 ffff88042dbb0000 ffffffff81c18900
Call Trace:
 [<ffffffff816152c5>] dump_stack+0x67/0x92
 [<ffffffff810d5bab>] __warn+0xcb/0xf0
 [<ffffffff810d5c1f>] warn_slowpath_fmt+0x4f/0x60
 [<ffffffff8110efae>] detach_task_cfs_rq+0x6fe/0x930
 [<ffffffff8110f1f1>] switched_from_fair+0x11/0x20
 [<ffffffff810fde77>] __sched_setscheduler+0x2a7/0xb40
 [<ffffffff810fe779>] _sched_setscheduler+0x69/0x70
 [<ffffffff810ff243>] sched_set_stop_task+0x53/0x90
 [<ffffffff81173703>] cpu_stop_create+0x23/0x30
 [<ffffffff810f90c0>] __smpboot_create_thread.part.2+0xb0/0x100
 [<ffffffff810f91ef>] smpboot_register_percpu_thread_cpumask+0xdf/0x140
 [<ffffffff823c24e7>] ? pid_namespaces_init+0x40/0x40
 [<ffffffff823c254b>] cpu_stop_init+0x64/0x9b
 [<ffffffff8100040d>] do_one_initcall+0x3d/0x150
 [<ffffffff8107763d>] ? print_cpu_info+0x7d/0xe0
 [<ffffffff823a0001>] kernel_init_freeable+0xcc/0x207
 [<ffffffff81a7d8d0>] ? rest_init+0x90/0x90
 [<ffffffff81a7d8de>] kernel_init+0xe/0x100
 [<ffffffff81a89bc7>] ret_from_fork+0x27/0x40
4---[ end trace 90bea7c93d2289cb ]---

  reply	other threads:[~2016-10-03 14:43 UTC|newest]

Thread overview: 44+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-21 13:38 [PATCH v2 0/7] sched: Diagnostic checks for missing rq clock updates Matt Fleming
2016-09-21 13:38 ` [PATCH v2 1/7] sched/fair: Update the rq clock before detaching tasks Matt Fleming
2016-10-03 12:49   ` Peter Zijlstra
2016-10-03 14:37     ` Matt Fleming
2016-10-03 14:42       ` Peter Zijlstra [this message]
2016-09-21 13:38 ` [PATCH v2 2/7] sched/fair: Update rq clock before waking up new task Matt Fleming
2016-09-21 13:38 ` [PATCH v2 3/7] sched/fair: Update rq clock in task_hot() Matt Fleming
2016-09-21 13:38 ` [PATCH v2 4/7] sched: Add wrappers for lockdep_(un)pin_lock() Matt Fleming
2017-01-14 12:40   ` [tip:sched/core] sched/core: " tip-bot for Matt Fleming
2016-09-21 13:38 ` [PATCH v2 5/7] sched/core: Reset RQCF_ACT_SKIP before unpinning rq->lock Matt Fleming
2017-01-14 12:41   ` [tip:sched/core] " tip-bot for Matt Fleming
2016-09-21 13:38 ` [PATCH v2 6/7] sched/fair: Push rq lock pin/unpin into idle_balance() Matt Fleming
2017-01-14 12:41   ` [tip:sched/core] " tip-bot for Matt Fleming
2016-09-21 13:38 ` [PATCH v2 7/7] sched/core: Add debug code to catch missing update_rq_clock() Matt Fleming
2016-09-21 15:58   ` Petr Mladek
2016-09-21 19:08     ` Matt Fleming
2016-09-21 19:46       ` Thomas Gleixner
2016-09-22  0:44       ` Sergey Senozhatsky
2016-09-22  8:04     ` Peter Zijlstra
2016-09-22  8:36       ` Jan Kara
2016-09-22  9:39         ` Peter Zijlstra
2016-09-22 10:17           ` Peter Zijlstra
2017-01-14 12:44   ` [tip:sched/core] sched/core: Add debugging code to catch missing update_rq_clock() calls tip-bot for Matt Fleming
     [not found]     ` <87tw8gutp6.fsf@concordia.ellerman.id.au>
2017-01-30 21:34       ` Matt Fleming
2017-01-31  8:35         ` Michael Ellerman
2017-01-31 11:00         ` Sachin Sant
2017-01-31 11:48           ` Mike Galbraith
2017-01-31 17:22             ` Ross Zwisler
2017-02-02 15:55               ` Peter Zijlstra
2017-02-02 22:01                 ` Matt Fleming
2017-02-03  3:05                 ` Mike Galbraith
2017-02-03  4:33                 ` Sachin Sant
2017-02-03  8:53                   ` Peter Zijlstra
2017-02-03 12:59                     ` Mike Galbraith
2017-02-03 13:37                       ` Peter Zijlstra
2017-02-03 13:52                         ` Mike Galbraith
2017-02-03 15:44                         ` Paul E. McKenney
2017-02-03 15:54                           ` Paul E. McKenney
2017-02-06  6:23                             ` Sachin Sant
2017-02-06 15:10                               ` Paul E. McKenney
2017-02-06 15:14                                 ` Paul E. McKenney
2017-02-03 13:04                 ` Borislav Petkov
2017-02-22  9:03                 ` Wanpeng Li
2017-02-24  9:16                 ` [tip:sched/urgent] sched/core: Fix update_rq_clock() splat on hotplug (and suspend/resume) tip-bot for Peter Zijlstra

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