From: Thomas Gleixner <tglx@linutronix.de>
To: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: 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>,
Sebastian Sewior <bigeasy@linutronix.de>
Subject: Re: WARN_ON_ONCE(!new_owner) within wake_futex_pi() triggered
Date: Tue, 29 Jan 2019 10:45:44 +0100 (CET) [thread overview]
Message-ID: <alpine.DEB.2.21.1901291012330.1669@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20190129090108.GA26906@osiris>
On Tue, 29 Jan 2019, Heiko Carstens wrote:
> On Mon, Jan 28, 2019 at 04:53:19PM +0100, Thomas Gleixner wrote:
> > Patch below cures that.
>
> With your patch the kernel warning doesn't occur anymore. So if this
> is supposed to be the fix feel free to add:
Yes, it's supposed to be the fix.
>
> However now I see every now and then the following failure from the
> same test case:
>
> tst-robustpi8: ../nptl/pthread_mutex_lock.c:425: __pthread_mutex_lock_full: Assertion `INTERNAL_SYSCALL_ERRNO (e, __err) != ESRCH || !robust' failed.
>
> /* ESRCH can happen only for non-robust PI mutexes where
> the owner of the lock died. */
> assert (INTERNAL_SYSCALL_ERRNO (e, __err) != ESRCH || !robust);
>
> I just verified that this happened also without your patch, I just
> didn't see it since I started my tests with panic_on_warn=1 and the
> warning triggered always earlier.
> So, this seems to be something different.
Moo. I ran the test loop all night (simply because I forgot to stop it) and
of course this does not trigger here. Could you try to gather a bit more
information with lightweight tracing?
Something like the below should give us at least a clue. Stop the tst loop
when the assert triggers and then extract the trace.
Thanks,
tglx
8<--------------
#!/bin/sh
# Substitute with your ld comm string if it starts differently
C=ld-linux
echo 'comm ~ "$C*"' >/sys/kernel/debug/tracing/events/syscalls/sys_enter_futex/filter
echo 'comm ~ "$C*"' >/sys/kernel/debug/tracing/events/syscalls/sys_exit_futex/filter
echo 'comm ~ "$C*"' >/sys/kernel/debug/tracing/events/sched/sched_process_exit/filter
echo 'prev_comm ~ "$C*" || next_comm ~ "$C*"' >/sys/kernel/debug/tracing/events/sched/sched_switch/filter
echo 1 > /sys/kernel/debug/tracing/events/syscalls/sys_enter_futex/enable
echo 1 > /sys/kernel/debug/tracing/events/syscalls/sys_exit_futex/enable
echo 1 > /sys/kernel/debug/tracing/events/sched/sched_process_exit/enable
echo 1 > /sys/kernel/debug/tracing/events/sched/sched_switch/enable
next prev parent reply other threads:[~2019-01-29 9:45 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 [this message]
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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