From: Peter Zijlstra <peterz@infradead.org>
To: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Sven Schnelle <svens@linux.ibm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
the arch/x86 maintainers <x86@kernel.org>
Subject: Re: [GIT pull] locking/urgent for v5.10-rc6
Date: Tue, 1 Dec 2020 15:55:19 +0100 [thread overview]
Message-ID: <20201201145519.GY2414@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20201201144644.GF1437@paulmck-ThinkPad-P72>
On Tue, Dec 01, 2020 at 06:46:44AM -0800, Paul E. McKenney wrote:
> > So after having talked to Sven a bit, the thing that is happening, is
> > that this is the one place where we take interrupts with RCU being
> > disabled. Normally RCU is watching and all is well, except during idle.
>
> Isn't interrupt entry supposed to invoke rcu_irq_enter() at some point?
> Or did this fall victim to recent optimizations?
It does, but the problem is that s390 is still using
trace_hardirqs_off(), which calls into tracing before RCU is enabled.
The entry order between lockdep, rcu and tracing is critical.
You can't call into tracing without RCU running,
you can't call into RCU without lockdep setup,
you can't call the (old) lockdep setup without landing in tracing.
next prev parent reply other threads:[~2020-12-01 14:56 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-29 13:37 [GIT pull] irq/urgent for v5.10-rc6 Thomas Gleixner
2020-11-29 13:38 ` [GIT pull] locking/urgent " Thomas Gleixner
2020-11-29 19:31 ` Linus Torvalds
2020-11-30 0:29 ` Paul E. McKenney
2020-11-30 7:56 ` Peter Zijlstra
2020-11-30 8:23 ` Sven Schnelle
2020-11-30 12:31 ` Sven Schnelle
2020-11-30 12:52 ` Peter Zijlstra
2020-11-30 13:03 ` Peter Zijlstra
2020-11-30 18:04 ` Linus Torvalds
2020-11-30 19:31 ` Christian Borntraeger
2020-12-01 8:07 ` Peter Zijlstra
2020-12-01 11:07 ` Peter Zijlstra
2020-12-01 14:46 ` Paul E. McKenney
2020-12-01 14:55 ` Peter Zijlstra [this message]
2020-12-01 16:53 ` Paul E. McKenney
2020-12-01 18:15 ` Peter Zijlstra
2020-12-01 18:48 ` Peter Zijlstra
2020-12-01 18:57 ` Mark Rutland
2020-12-01 19:14 ` Peter Zijlstra
2020-12-01 19:18 ` Heiko Carstens
2020-12-02 9:21 ` Peter Zijlstra
2020-12-02 10:56 ` Heiko Carstens
2020-12-02 11:16 ` Mark Rutland
2020-12-02 13:46 ` Heiko Carstens
2020-12-02 12:27 ` Peter Zijlstra
2020-12-01 7:48 ` Sven Schnelle
2020-12-02 7:54 ` Heiko Carstens
2020-12-02 9:38 ` Peter Zijlstra
2020-12-02 10:52 ` Heiko Carstens
2020-11-30 8:36 ` Peter Zijlstra
2020-11-30 17:55 ` Linus Torvalds
2020-12-01 7:39 ` Peter Zijlstra
2020-12-01 7:56 ` Peter Zijlstra
2020-12-01 19:45 ` Linus Torvalds
2020-12-02 7:53 ` Peter Zijlstra
2020-11-29 20:06 ` pr-tracker-bot
2020-11-29 20:06 ` [GIT pull] irq/urgent " pr-tracker-bot
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