From: Heiko Carstens <heiko.carstens@de.ibm.com>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Sebastian Sewior <bigeasy@linutronix.de>,
"Paul E. McKenney" <paulmck@linux.ibm.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
LKML <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() triggerede
Date: Mon, 4 Feb 2019 12:40:09 +0100 [thread overview]
Message-ID: <20190204114009.GA3687@osiris> (raw)
In-Reply-To: <alpine.DEB.2.21.1902031718170.8200@nanos.tec.linutronix.de>
On Sun, Feb 03, 2019 at 05:30:39PM +0100, Thomas Gleixner wrote:
> On Sat, 2 Feb 2019, Heiko Carstens wrote:
> > I added a barrier between those two and now the code looks like this:
> >
> > 140: a5 1b 00 01 oill %r1,1
> > 144: e3 10 a0 e0 00 24 stg %r1,224(%r10)
> > 14a: e5 48 a0 f0 00 00 mvghi 240(%r10),0
> >
> > Looks like this was a one instruction race...
>
> Fun. JFYI, I said that I reversed the stores in glibc and on my x86 test VM
> it took more than _3_ days to trigger. But the good news is, that the trace
> looks exactly like the ones you provided. So it looks we are on the right
> track.
>
> > I'll try to reproduce with the patch below (sprinkling compiler
> > barriers just like the other files have).
>
> Looks about right.
The test case now runs since two days without failures. So it looks like you
found the bug! Thank you for debugging this!
My glibc patch missed at lease one place where I should have added another
barrier, but the current version was good enough for the test case ;)
Stefan Liebler is kind enough to take care that this will be fixed in glibc.
Thanks!
next prev parent reply other threads:[~2019-02-04 11:40 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
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 [this message]
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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