From: Thomas Gleixner <tglx@linutronix.de>
To: Mike Galbraith <efault@gmx.de>,
Gratian Crisan <gratian.crisan@ni.com>,
Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org,
Brandon Streiff <brandon.streiff@ni.com>,
Ingo Molnar <mingo@redhat.com>,
Darren Hart <dvhart@infradead.org>,
James Minor <james.minor@ni.com>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Subject: Re: [PATCH] futex: Handle transient "ownerless" rtmutex state correctly
Date: Wed, 04 Nov 2020 16:22:04 +0100 [thread overview]
Message-ID: <87pn4tkuzn.fsf@nanos.tec.linutronix.de> (raw)
In-Reply-To: <87sg9pkvf7.fsf@nanos.tec.linutronix.de>
On Wed, Nov 04 2020 at 16:12, Thomas Gleixner wrote:
> From: Mike Galbraith <efault@gmx.de>
>
> Gratian managed to trigger the BUG_ON(!newowner) in fixup_pi_state_owner().
> This is one possible chain of events leading to this:
>
> Task Prio Operation
> T1 120 lock(F)
> T2 120 lock(F) -> blocks (top waiter)
> T3 50 (RT) lock(F) -> boosts T3 and blocks (new top waiter)
boosts T1 obviously as Sebastian just pointed out to me. /me pulls the
futex induced brain damage excuse ...
next prev parent reply other threads:[~2020-11-04 15:22 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-28 23:24 BUG_ON(!newowner) in fixup_pi_state_owner() Gratian Crisan
2020-11-03 23:31 ` Gratian Crisan
2020-11-04 0:56 ` Mike Galbraith
2020-11-04 7:42 ` Mike Galbraith
2020-11-04 10:24 ` Thomas Gleixner
2020-11-04 11:17 ` Thomas Gleixner
2020-11-04 13:26 ` Thomas Gleixner
2020-11-04 13:43 ` Mike Galbraith
2020-11-04 15:12 ` [PATCH] futex: Handle transient "ownerless" rtmutex state correctly Thomas Gleixner
2020-11-04 15:22 ` Thomas Gleixner [this message]
2020-11-04 16:50 ` Mike Galbraith
2020-11-05 6:32 ` Gratian Crisan
2020-11-04 10:00 ` BUG_ON(!newowner) in fixup_pi_state_owner() Thomas Gleixner
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