From: Steven Rostedt <rostedt@goodmis.org>
To: Sedat Dilek <sedat.dilek@gmail.com>
Cc: Paul McKenney <paulmck@linux.vnet.ibm.com>,
Dave Hansen <dave@sr71.net>,
"Rafael J. Wysocki" <rjw@rjwysocki.net>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
linux-next <linux-next@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Stephen Rothwell <sfr@canb.auug.org.au>,
Kristen Carlson Accardi <kristen@linux.intel.com>,
"H. Peter Anvin" <hpa@linux.intel.com>,
Rik van Riel <riel@redhat.com>, Mel Gorman <mgorman@suse.de>
Subject: Re: linux-next: Tree for Feb 4
Date: Thu, 5 Feb 2015 14:58:16 -0500 [thread overview]
Message-ID: <20150205145816.7c38a7df@gandalf.local.home> (raw)
In-Reply-To: <CA+icZUX_fi-O3kXymLCPfJ8Sx0yG=m5=pWzJDJpu-iHTyjM78Q@mail.gmail.com>
On Thu, 5 Feb 2015 20:25:21 +0100
Sedat Dilek <sedat.dilek@gmail.com> wrote:
> On Thu, Feb 5, 2015 at 7:45 PM, Paul E. McKenney
> <paulmck@linux.vnet.ibm.com> wrote:
> > On Thu, Feb 05, 2015 at 10:35:33AM -0800, Dave Hansen wrote:
> >> On 02/05/2015 10:34 AM, Paul E. McKenney wrote:
> >> >> > Did I actually need to be
> >> >> > onlining/offlining CPUs to hit the splat that Sedat was reporting?
> >> > Yep, you do need to offline at least one CPU to hit that splat.
> >>
> >> Heh, do we need a debugging mode that will randomly offline/online CPUs? :)
> >
> > For that, kernel/rcu/rcutorture.c and kernel/locking/locktorture.c
> > are your friends. ;-)
> >
> > The problem is that I only run RCU-relevant combinations of Kconfigs,
> > which means that I missed the ones that Sedat used to find this problem.
> > So I guess it is a good thing that others run -next testing.
> >
>
> [ Revived by a voltaren resinat pill... ]
>
> I reverted "x86/mm: Omit switch_mm() tracing for offline CPUs"
> ...and...
> applied "tlb: Don't do trace_tlb_flush() on offline CPUs"
> ...in my build-dir.
Is this Paul's version of the patch or mine? If it is just mine, do you
know if Paul's version triggers this too?
> ( I did not build from scratch but re-invoking make "updated" the
> files touched by Steven's patch, see attached build-log. )
>
> Unfortunately, the call-trace remains when doing an offlining of cpu1.
> ( It's good to see it's reproducible. )
Was the tracepoint enabled? Or was there some other rcu call that
triggered this. Or would cpu_online(smp_processor_id()) return true at
this point?
-- Steve
>
> root# echo 0 > /sys/devices/system/cpu/cpu1/online
>
> [ 121.652796] intel_pstate CPU 1 exiting
> [ 121.666272]
> [ 121.666274] ===============================
> [ 121.666274] [ INFO: suspicious RCU usage. ]
> [ 121.666277] 3.19.0-rc7-next-20150204.7-iniza-small #4 Not tainted
> [ 121.666278] -------------------------------
> [ 121.666280] include/trace/events/tlb.h:37 suspicious
> rcu_dereference_check() usage!
> [ 121.666281]
> [ 121.666281] other info that might help us debug this:
> [ 121.666281]
> [ 121.666282]
> [ 121.666282] RCU used illegally from offline CPU!
> [ 121.666282] rcu_scheduler_active = 1, debug_locks = 0
> [ 121.666283] no locks held by swapper/1/0.
> [ 121.666284]
> [ 121.666284] stack backtrace:
> [ 121.666287] CPU: 1 PID: 0 Comm: swapper/1 Not tainted
> 3.19.0-rc7-next-20150204.7-iniza-small #4
> [ 121.666288] Hardware name: SAMSUNG ELECTRONICS CO., LTD.
> 530U3BI/530U4BI/530U4BH/530U3BI/530U4BI/530U4BH, BIOS 13XK 03/28/2013
> [ 121.666293] 0000000000000001 ffff88011a44fe18 ffffffff817e39cd
> 0000000000000011
> [ 121.666296] ffff88011a448290 ffff88011a44fe48 ffffffff810d6af7
> ffff8800d3dfaac0
> [ 121.666299] 0000000000000001 ffffffff81d32ce0 0000000000000005
> ffff88011a44fe78
> [ 121.666300] Call Trace:
> [ 121.666308] [<ffffffff817e39cd>] dump_stack+0x4c/0x65
> [ 121.666313] [<ffffffff810d6af7>] lockdep_rcu_suspicious+0xe7/0x120
> [ 121.666318] [<ffffffff810b73f9>] idle_task_exit+0x1c9/0x260
> [ 121.666322] [<ffffffff81054c4e>] play_dead_common+0xe/0x50
> [ 121.666325] [<ffffffff81054ca5>] native_play_dead+0x15/0x140
> [ 121.666330] [<ffffffff8102963f>] arch_cpu_idle_dead+0xf/0x20
> [ 121.666333] [<ffffffff810cdb4e>] cpu_startup_entry+0x37e/0x580
> [ 121.666336] [<ffffffff81053e20>] start_secondary+0x140/0x150
> [ 121.666744] smpboot: CPU 1 is now offline
>
> >From rcu point this is now safe?
> But another area (linux-pm?) is still affected?
> I will try to test "vanilla" pm-next if the problem exists with
> intel_pstate as suggested by Rafael.
> Hmmm, not sure how I can get the pm-next code which went into
> next-20150204 as linux-pm.git#linux-next was feeded with new stuff.
>
>
> - Sedat -
next prev parent reply other threads:[~2015-02-05 19:58 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-04 8:35 linux-next: Tree for Feb 4 Stephen Rothwell
2015-02-04 12:26 ` Sedat Dilek
2015-02-04 15:16 ` Jens Axboe
2015-02-04 15:21 ` Sedat Dilek
2015-02-04 15:31 ` Jens Axboe
2015-02-04 15:36 ` Sedat Dilek
2015-02-04 15:58 ` Martin K. Petersen
2015-02-04 16:06 ` Sedat Dilek
2015-02-05 3:17 ` Martin K. Petersen
2015-02-05 3:41 ` Sedat Dilek
2015-02-05 19:46 ` Sedat Dilek
2015-02-06 15:24 ` Sedat Dilek
2015-02-04 20:18 ` Sedat Dilek
2015-02-04 21:54 ` Rafael J. Wysocki
2015-02-04 21:53 ` Paul E. McKenney
2015-02-04 22:59 ` Rafael J. Wysocki
2015-02-04 23:51 ` Paul E. McKenney
2015-02-04 23:58 ` Sedat Dilek
2015-02-05 0:10 ` Paul E. McKenney
2015-02-05 0:30 ` Sedat Dilek
2015-02-05 0:57 ` Paul E. McKenney
2015-02-05 1:18 ` Sedat Dilek
2015-02-05 1:51 ` Paul E. McKenney
2015-02-05 1:53 ` Sedat Dilek
2015-02-05 2:12 ` Sedat Dilek
2015-02-05 4:13 ` Paul E. McKenney
2015-02-05 7:14 ` Dave Hansen
2015-02-05 14:37 ` Paul E. McKenney
2015-02-05 14:57 ` Sedat Dilek
2015-02-05 16:58 ` Paul E. McKenney
2015-02-05 18:03 ` Steven Rostedt
2015-02-05 18:08 ` Steven Rostedt
2015-02-05 18:11 ` Dave Hansen
2015-02-05 18:34 ` Paul E. McKenney
2015-02-05 18:35 ` Dave Hansen
2015-02-05 18:45 ` Paul E. McKenney
2015-02-05 19:25 ` Sedat Dilek
2015-02-05 19:33 ` Paul E. McKenney
2015-02-05 19:42 ` Sedat Dilek
2015-02-05 19:58 ` Steven Rostedt [this message]
2015-02-05 20:07 ` Sedat Dilek
2015-02-05 20:22 ` Steven Rostedt
2015-02-05 20:50 ` Sedat Dilek
2015-02-05 21:45 ` Sedat Dilek
2015-02-05 22:09 ` Steven Rostedt
2015-02-05 22:16 ` Sedat Dilek
2015-02-05 23:11 ` Steven Rostedt
2015-02-05 23:53 ` Sedat Dilek
2015-02-06 0:03 ` Sedat Dilek
2015-02-06 0:12 ` Steven Rostedt
2015-02-06 0:14 ` Sedat Dilek
2015-02-04 22:38 ` Sedat Dilek
2015-02-04 23:25 ` Rafael J. Wysocki
2015-02-04 23:54 ` Sedat Dilek
2015-02-04 22:46 ` Sedat Dilek
2015-02-04 23:30 ` Rafael J. Wysocki
2015-02-04 23:48 ` Sedat Dilek
-- strict thread matches above, loose matches on Subject: below --
2022-02-04 4:14 Stephen Rothwell
2021-02-04 9:13 Stephen Rothwell
2020-02-04 4:19 Stephen Rothwell
2019-02-04 5:35 Stephen Rothwell
2016-02-04 3:48 Stephen Rothwell
2014-02-04 5:07 Stephen Rothwell
[not found] ` <CAP=VYLpgLC_4yuPtQH_yAd8S9cqQAVu2uB2=Wf3q_zgY4uzkLw@mail.gmail.com>
2014-02-04 22:23 ` Stephen Rothwell
2014-02-05 0:41 ` Stephen Rothwell
2013-02-04 7:39 Stephen Rothwell
2013-02-04 13:56 ` James Hogan
2013-02-04 20:33 ` Stephen Rothwell
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