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From: Heiko Carstens <heiko.carstens@de.ibm.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@kernel.org>,
	Martin Schwidefsky <schwidefsky@de.ibm.com>,
	linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org,
	Stefan Liebler <stli@linux.ibm.com>
Subject: Re: WARN_ON_ONCE(!new_owner) within wake_futex_pi() triggered
Date: Thu, 29 Nov 2018 12:23:21 +0100	[thread overview]
Message-ID: <20181129112321.GB3449@osiris> (raw)
In-Reply-To: <alpine.DEB.2.21.1811281526430.1532@nanos.tec.linutronix.de>

On Wed, Nov 28, 2018 at 03:32:45PM +0100, Thomas Gleixner wrote:
> Heiko,
> 
> On Tue, 27 Nov 2018, Heiko Carstens wrote:
> 
> > with the glibc self-tests I was able to trigger the "this should not
> > happen" warning ;) below on s390 (with panic_on_warn=1 set). It looks
> > like it is hardly reproducible.
> 
> Any idea which self-test triggered that?
> 
> > This one happened with commit d146194f31c9 for compiling the kernel.
> > Config can be re-created with "make ARCH=s390 performance_defconfig".
> 
> Which is not really helpful for people who do not own a s390. And no, I
> don't want one unless IBM pays the power bill as well :)
> 
> > [  649.596938] WARNING: CPU: 0 PID: 58886 at kernel/futex.c:1418 do_futex+0xa9a/0xc50
> > [  649.596946] Kernel panic - not syncing: panic_on_warn set ...
> > [  649.596951] CPU: 0 PID: 58886 Comm: ld64.so.1 Not tainted 4.20.0-20181125.rc3.git0.d146194f31c9.300.fc29.s390x+git #1
> 
> That's ld64.so.1. Weird, but what do I know about glibc self tests.
> 
> I still fail to see how that can happen, but I usually page out the futex
> horrors immediately. I'll keep staring at the code...

I looked into the system dumps, and if I didn't screw up, then the
command line for both occurrences was

/root/glibc-build/nptl/tst-robustpi8

And indeed, if I run only this test case in an endless loop and do
some parallel work (like kernel compile) it currently seems to be
possible to reproduce the warning:

while true; do time ./testrun.sh nptl/tst-robustpi8 --direct ; done

within the build directory of glibc (2.28).

See
https://sourceware.org/git/?p=glibc.git;a=blob;f=nptl/tst-robustpi8.c;h=cbea3d6d77abb00be05ec7b466d8339c26dd2efb;hb=3c03baca37fdcb52c3881e653ca392bba7a99c2b

which includes this one:

https://sourceware.org/git/?p=glibc.git;a=blob;f=nptl/tst-robust8.c;h=9c636250d4cb0bcd6d802910e8f9ea31568bb73f;hb=3c03baca37fdcb52c3881e653ca392bba7a99c2b


  reply	other threads:[~2018-11-29 11:23 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-27  8:11 WARN_ON_ONCE(!new_owner) within wake_futex_pi() triggered Heiko Carstens
2018-11-28 14:32 ` Thomas Gleixner
2018-11-29 11:23   ` Heiko Carstens [this message]
2019-01-21 12:21     ` Heiko Carstens
2019-01-21 13:12       ` Thomas Gleixner
2019-01-22 21:14         ` Thomas Gleixner
2019-01-23  9:24           ` Heiko Carstens
2019-01-23 12:33             ` Thomas Gleixner
2019-01-23 12:40               ` Heiko Carstens
2019-01-28 13:44     ` Peter Zijlstra
2019-01-28 13:58       ` Peter Zijlstra
2019-01-28 15:53         ` Thomas Gleixner
2019-01-29  8:49           ` Peter Zijlstra
2019-01-29 22:15             ` [PATCH] futex: Handle early deadlock return correctly Thomas Gleixner
2019-01-30 12:01               ` Thomas Gleixner
2019-02-08 12:05               ` [tip:locking/urgent] " tip-bot for Thomas Gleixner
2019-01-29  9:01           ` WARN_ON_ONCE(!new_owner) within wake_futex_pi() triggered Heiko Carstens
2019-01-29  9:33             ` Peter Zijlstra
2019-01-29  9:45             ` Thomas Gleixner
2019-01-29 10:24               ` Heiko Carstens
2019-01-29 10:35                 ` Peter Zijlstra
2019-01-29 13:03                   ` Thomas Gleixner
2019-01-29 13:23                     ` Heiko Carstens
     [not found]                       ` <20190129151058.GG26906@osiris>
2019-01-29 17:16                         ` Sebastian Sewior
2019-01-29 21:45                           ` Thomas Gleixner
     [not found]                           ` <20190130094913.GC5299@osiris>
2019-01-30 12:15                             ` Thomas Gleixner
     [not found]                               ` <20190130125955.GD5299@osiris>
2019-01-30 13:24                                 ` Sebastian Sewior
2019-01-30 13:29                                   ` Thomas Gleixner
2019-01-30 14:33                                     ` Thomas Gleixner
2019-01-30 17:56                                       ` Thomas Gleixner
2019-01-30 21:07                                         ` Sebastian Sewior
2019-01-30 23:13                                           ` WARN_ON_ONCE(!new_owner) within wake_futex_pi() triggerede Thomas Gleixner
2019-01-30 23:35                                             ` Paul E. McKenney
2019-01-30 23:55                                               ` Thomas Gleixner
2019-01-31  0:27                                                 ` Thomas Gleixner
2019-01-31  1:45                                                   ` Paul E. McKenney
2019-01-31 16:52                                                   ` Heiko Carstens
2019-01-31 17:06                                                     ` Sebastian Sewior
2019-01-31 20:42                                                       ` Heiko Carstens
2019-02-01 16:12                                                       ` Heiko Carstens
2019-02-01 21:59                                                         ` Thomas Gleixner
     [not found]                                                           ` <20190202091043.GA3381@osiris>
2019-02-02 10:14                                                             ` Thomas Gleixner
2019-02-02 11:20                                                               ` Heiko Carstens
2019-02-03 16:30                                                                 ` Thomas Gleixner
2019-02-04 11:40                                                                   ` Heiko Carstens
2019-01-31  1:44                                                 ` Paul E. McKenney
2019-01-30 13:25                                 ` WARN_ON_ONCE(!new_owner) within wake_futex_pi() triggered Thomas Gleixner

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