From: Ross Zwisler <zwisler@gmail.com>
To: Mike Galbraith <efault@gmx.de>
Cc: Sachin Sant <sachinp@linux.vnet.ibm.com>,
Matt Fleming <matt@codeblueprint.co.uk>,
Michael Ellerman <mpe@ellerman.id.au>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
peterz@infradead.org,
"linux-next@vger.kernel.org" <linux-next@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [tip:sched/core] sched/core: Add debugging code to catch missing update_rq_clock() calls
Date: Tue, 31 Jan 2017 10:22:47 -0700 [thread overview]
Message-ID: <CAOxpaSW_GnndoxLBPtyTrqPJ9XOWvgXOQNDf8D+6OohWeObn5Q@mail.gmail.com> (raw)
In-Reply-To: <1485863317.4498.2.camel@gmx.de>
On Tue, Jan 31, 2017 at 4:48 AM, Mike Galbraith <efault@gmx.de> wrote:
> On Tue, 2017-01-31 at 16:30 +0530, Sachin Sant wrote:
>> Trimming the cc list.
>>
>> > > I assume I should be worried?
>> >
>> > Thanks for the report. No need to worry, the bug has existed for a
>> > while, this patch just turns on the warning ;-)
>> >
>> > The following commit queued up in tip/sched/core should fix your
>> > issues (assuming you see the same callstack on all your powerpc
>> > machines):
>> >
>> > https://git.kernel.org/cgit/linux/kernel/git/tip/tip.git/commit/?h=sched/core&id=1b1d62254df0fe42a711eb71948f915918987790
>>
>> I still see this warning with today’s next running inside PowerVM LPAR
>> on a POWER8 box. The stack trace is different from what Michael had
>> reported.
>>
>> Easiest way to recreate this is to Online/offline cpu’s.
>
> (Ditto tip.today, x86_64 + hotplug stress)
<>
I'm also seeing a splat in the mmots tree with
v4.10-rc5-mmots-2017-01-26-15-49, which pulled in this commit by
merging with next. Just booting on an x86_64 VM gives me this:
[ 13.090436] ------------[ cut here ]------------
[ 13.090577] WARNING: CPU: 8 PID: 1 at kernel/sched/sched.h:804
update_load_avg+0x85b/0xb80
[ 13.090577] rq->clock_update_flags < RQCF_ACT_SKIP
[ 13.090578] Modules linked in: dax_pmem dax nd_pmem nd_btt nd_e820 libnvdimm
[ 13.090582] CPU: 8 PID: 1 Comm: systemd Not tainted
4.10.0-rc5-mm1-00313-g5c0c3d7-dirty #10
[ 13.090583] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS rel-1.9.1-0-gb3ef39f-prebuilt.qemu-project.org 04/01/2014
[ 13.090583] Call Trace:
[ 13.090585] dump_stack+0x86/0xc3
[ 13.090586] __warn+0xcb/0xf0
[ 13.090588] warn_slowpath_fmt+0x5f/0x80
[ 13.090590] update_load_avg+0x85b/0xb80
[ 13.090591] ? debug_smp_processor_id+0x17/0x20
[ 13.090593] detach_task_cfs_rq+0x3f/0x210
[ 13.090594] task_change_group_fair+0x24/0x100
[ 13.090596] sched_change_group+0x5f/0x110
[ 13.090597] sched_move_task+0x53/0x160
[ 13.090598] cpu_cgroup_attach+0x36/0x70
[ 13.090600] cgroup_migrate_execute+0x230/0x3f0
[ 13.090602] cgroup_migrate+0xce/0x140
[ 13.090603] ? cgroup_migrate+0x5/0x140
[ 13.090604] cgroup_attach_task+0x27f/0x3e0
[ 13.090606] ? cgroup_attach_task+0x9b/0x3e0
[ 13.090608] __cgroup_procs_write+0x30e/0x510
[ 13.090608] ? __cgroup_procs_write+0x70/0x510
[ 13.090610] cgroup_procs_write+0x14/0x20
[ 13.090611] cgroup_file_write+0x44/0x1e0
[ 13.090613] kernfs_fop_write+0x13c/0x1c0
[ 13.090614] __vfs_write+0x37/0x160
[ 13.090615] ? rcu_read_lock_sched_held+0x4a/0x80
[ 13.090616] ? rcu_sync_lockdep_assert+0x2f/0x60
[ 13.090617] ? __sb_start_write+0x10d/0x220
[ 13.090618] ? vfs_write+0x19b/0x1f0
[ 13.090619] ? security_file_permission+0x3b/0xc0
[ 13.090620] vfs_write+0xcb/0x1f0
[ 13.090621] SyS_write+0x58/0xc0
[ 13.090623] entry_SYSCALL_64_fastpath+0x1f/0xc2
[ 13.090623] RIP: 0033:0x7f8b7c1be210
[ 13.090624] RSP: 002b:00007ffe73febfd8 EFLAGS: 00000246 ORIG_RAX:
0000000000000001
[ 13.090625] RAX: ffffffffffffffda RBX: 000055a84870a7e0 RCX: 00007f8b7c1be210
[ 13.090625] RDX: 0000000000000004 RSI: 000055a84870aa10 RDI: 0000000000000033
[ 13.090626] RBP: 0000000000000000 R08: 000055a84870a8c0 R09: 00007f8b7dbda900
[ 13.090627] R10: 000055a84870aa10 R11: 0000000000000246 R12: 0000000000000000
[ 13.090627] R13: 000055a848775360 R14: 000055a84870a7e0 R15: 0000000000000033
[ 13.090629] ---[ end trace ba535936c2409043 ]---
next prev parent reply other threads:[~2017-01-31 17:24 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
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 [this message]
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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