From: Boqun Feng <boqun@kernel.org>
To: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
frederic@kernel.org, neeraj.iitr10@gmail.com, urezki@gmail.com,
joelagnelf@nvidia.com, boqun.feng@gmail.com, rcu@vger.kernel.org,
Kumar Kartikeya Dwivedi <memxor@gmail.com>
Subject: Re: Next-level bug in SRCU implementation of RCU Tasks Trace + PREEMPT_RT
Date: Wed, 18 Mar 2026 09:42:09 -0700 [thread overview]
Message-ID: <abrV4VResx7QERRo@tardis.local> (raw)
In-Reply-To: <06a0cb91-1737-4691-a810-8340e1acf1d6@paulmck-laptop>
On Wed, Mar 18, 2026 at 09:32:07AM -0700, Paul E. McKenney wrote:
> On Wed, Mar 18, 2026 at 05:04:45PM +0100, Sebastian Andrzej Siewior wrote:
> > On 2026-03-18 08:43:32 [-0700], Paul E. McKenney wrote:
> > > > Your patch just s/spinlock_t/raw_spinlock_t so we get the locking/
> > > > nesting right. The wakeup problem remains, right?
> > > > But looking at the code, there is just srcu_funnel_gp_start(). If its
> > > > srcu_schedule_cbs_sdp() / queue_delayed_work() usage is always delayed
> > > > then there will be always a timer and never a direct wake up of the
> > > > worker. Wouldn't that work?
> > >
> > > Right, that patch fixes one lockdep problem, but another remains.
> >
> > What remains?
>
> With that patch, we no longer have call_srcu() directly acquiring a
> non-raw spinlock, but as you say, we still have the wakeup problem.
>
I don't think we have a wakeup problem since we use workqueue to defer
the wakeup, but maybe I'm missing something here?
Regards,
Boqun
next prev parent reply other threads:[~2026-03-18 16:42 UTC|newest]
Thread overview: 101+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-17 13:34 Next-level bug in SRCU implementation of RCU Tasks Trace + PREEMPT_RT Paul E. McKenney
2026-03-18 10:50 ` Sebastian Andrzej Siewior
2026-03-18 11:49 ` Paul E. McKenney
2026-03-18 14:43 ` Sebastian Andrzej Siewior
2026-03-18 15:43 ` Paul E. McKenney
2026-03-18 16:04 ` Sebastian Andrzej Siewior
2026-03-18 16:32 ` Paul E. McKenney
2026-03-18 16:42 ` Boqun Feng [this message]
2026-03-18 18:45 ` Paul E. McKenney
2026-03-18 16:47 ` Sebastian Andrzej Siewior
2026-03-18 18:48 ` Paul E. McKenney
2026-03-19 8:55 ` Sebastian Andrzej Siewior
2026-03-19 10:05 ` Paul E. McKenney
2026-03-19 10:43 ` Paul E. McKenney
2026-03-19 10:51 ` Sebastian Andrzej Siewior
2026-03-18 15:51 ` Boqun Feng
2026-03-18 18:42 ` Paul E. McKenney
2026-03-18 20:04 ` Joel Fernandes
2026-03-18 20:11 ` Kumar Kartikeya Dwivedi
2026-03-18 20:25 ` Joel Fernandes
2026-03-18 21:52 ` Boqun Feng
2026-03-18 21:55 ` Boqun Feng
2026-03-18 22:15 ` Boqun Feng
2026-03-18 22:52 ` Joel Fernandes
2026-03-18 23:27 ` Boqun Feng
2026-03-19 1:08 ` Boqun Feng
2026-03-19 9:03 ` Sebastian Andrzej Siewior
2026-03-19 16:27 ` Boqun Feng
2026-03-19 16:33 ` Sebastian Andrzej Siewior
2026-03-19 16:48 ` Boqun Feng
2026-03-19 16:59 ` Kumar Kartikeya Dwivedi
2026-03-19 17:27 ` Boqun Feng
2026-03-19 18:41 ` Kumar Kartikeya Dwivedi
2026-03-19 20:14 ` Boqun Feng
2026-03-19 20:21 ` Joel Fernandes
2026-03-19 20:39 ` Boqun Feng
2026-03-20 15:34 ` Paul E. McKenney
2026-03-20 15:59 ` Boqun Feng
2026-03-20 16:24 ` Paul E. McKenney
2026-03-20 16:57 ` Boqun Feng
2026-03-20 17:54 ` Joel Fernandes
2026-03-20 18:14 ` [PATCH] rcu: Use an intermediate irq_work to start process_srcu() Boqun Feng
2026-03-20 19:18 ` Joel Fernandes
2026-03-20 20:47 ` Andrea Righi
2026-03-20 20:54 ` Boqun Feng
2026-03-20 21:00 ` Andrea Righi
2026-03-20 21:02 ` Andrea Righi
2026-03-20 21:06 ` Boqun Feng
2026-03-20 22:29 ` [PATCH v2] " Boqun Feng
2026-03-23 21:09 ` Joel Fernandes
2026-03-23 22:18 ` Boqun Feng
2026-03-23 22:50 ` Joel Fernandes
2026-03-24 11:27 ` Frederic Weisbecker
2026-03-24 14:56 ` Joel Fernandes
2026-03-24 14:56 ` Alexei Starovoitov
2026-03-24 17:36 ` Boqun Feng
2026-03-24 18:40 ` Joel Fernandes
2026-03-24 19:23 ` Paul E. McKenney
2026-03-26 19:12 ` patchwork-bot+netdevbpf
2026-03-21 4:27 ` [PATCH] " Zqiang
2026-03-21 18:15 ` Boqun Feng
2026-03-21 10:10 ` Paul E. McKenney
2026-03-21 17:15 ` Boqun Feng
2026-03-21 17:41 ` Paul E. McKenney
2026-03-21 18:06 ` Boqun Feng
2026-03-21 19:31 ` Paul E. McKenney
2026-03-21 19:45 ` Boqun Feng
2026-03-21 20:07 ` Paul E. McKenney
2026-03-21 20:08 ` Boqun Feng
2026-03-22 10:09 ` Paul E. McKenney
2026-03-22 16:16 ` Boqun Feng
2026-03-22 17:09 ` Paul E. McKenney
2026-03-22 17:31 ` Boqun Feng
2026-03-22 17:44 ` Paul E. McKenney
2026-03-22 18:17 ` Boqun Feng
2026-03-22 19:47 ` Paul E. McKenney
2026-03-22 20:26 ` Boqun Feng
2026-03-23 7:50 ` Paul E. McKenney
2026-03-20 18:20 ` Next-level bug in SRCU implementation of RCU Tasks Trace + PREEMPT_RT Boqun Feng
2026-03-20 23:11 ` Paul E. McKenney
2026-03-21 3:29 ` Paul E. McKenney
2026-03-21 17:03 ` [RFC PATCH] rcu-tasks: Avoid using mod_timer() in call_rcu_tasks_generic() Boqun Feng
2026-03-23 15:17 ` Boqun Feng
2026-03-23 20:37 ` Joel Fernandes
2026-03-23 21:50 ` Kumar Kartikeya Dwivedi
2026-03-23 22:13 ` Boqun Feng
2026-03-20 16:15 ` Next-level bug in SRCU implementation of RCU Tasks Trace + PREEMPT_RT Boqun Feng
2026-03-20 16:24 ` Paul E. McKenney
2026-03-19 17:02 ` Sebastian Andrzej Siewior
2026-03-19 17:44 ` Boqun Feng
2026-03-19 18:42 ` Joel Fernandes
2026-03-19 20:20 ` Boqun Feng
2026-03-19 20:26 ` Joel Fernandes
2026-03-19 20:45 ` Joel Fernandes
2026-03-19 10:02 ` Paul E. McKenney
2026-03-19 14:34 ` Boqun Feng
2026-03-19 16:10 ` Paul E. McKenney
2026-03-18 23:56 ` Kumar Kartikeya Dwivedi
2026-03-19 0:26 ` Zqiang
2026-03-19 1:13 ` Boqun Feng
2026-03-19 2:47 ` Joel Fernandes
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=abrV4VResx7QERRo@tardis.local \
--to=boqun@kernel.org \
--cc=bigeasy@linutronix.de \
--cc=boqun.feng@gmail.com \
--cc=frederic@kernel.org \
--cc=joelagnelf@nvidia.com \
--cc=memxor@gmail.com \
--cc=neeraj.iitr10@gmail.com \
--cc=paulmck@kernel.org \
--cc=rcu@vger.kernel.org \
--cc=urezki@gmail.com \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.