From: "Paul E. McKenney" <paulmck@kernel.org>
To: Peter Zijlstra <peterz@infradead.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 08:53:21 -0800 [thread overview]
Message-ID: <20201201165321.GG1437@paulmck-ThinkPad-P72> (raw)
In-Reply-To: <20201201145519.GY2414@hirez.programming.kicks-ass.net>
On Tue, Dec 01, 2020 at 03:55:19PM +0100, Peter Zijlstra wrote:
> 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.
Whew! ;-)
Thanx, Paul
next prev parent reply other threads:[~2020-12-01 16:54 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
2020-12-01 16:53 ` Paul E. McKenney [this message]
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20201201165321.GG1437@paulmck-ThinkPad-P72 \
--to=paulmck@kernel.org \
--cc=borntraeger@de.ibm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=peterz@infradead.org \
--cc=svens@linux.ibm.com \
--cc=tglx@linutronix.de \
--cc=torvalds@linux-foundation.org \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).