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From: Steven Rostedt <rostedt@goodmis.org>
To: John Stultz <john.stultz@linaro.org>
Cc: paulmck@kernel.org, Josh Triplett <josh@joshtriplett.org>,
	lkml <linux-kernel@vger.kernel.org>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Saravana Kannan <saravanak@google.com>,
	Todd Kjos <tkjos@google.com>, Stephen Boyd <sboyd@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>
Subject: Re: On trace_*_rcuidle functions in modules
Date: Wed, 15 Apr 2020 16:41:16 -0400	[thread overview]
Message-ID: <20200415164116.40564f2c@gandalf.local.home> (raw)
In-Reply-To: <CALAqxLU26PVFPSza5GceSF6gTVdzo_2D3G0dBp0KZXvAWFUktA@mail.gmail.com>

On Wed, 15 Apr 2020 13:17:53 -0700
John Stultz <john.stultz@linaro.org> wrote:

> > Hmm, isn't module code itself synchronized via RCU. Then having module code
> > being called without RCU "watching" could be dangerous?  
> 
> I'm not sure I'm following you here. Could you explain more?

So how does this code get registered to be called as a module? And if it is
registered, I'm guessing it needs to be unregistered too. How would that be
synchronized? Usually, calling synchronize_rcu() is done after
unregistering, but if that code is called without RCU watching, it is
possible synchronize_rcu() can finish before that code is released.

-- Steve

  reply	other threads:[~2020-04-15 20:41 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-15  2:20 On trace_*_rcuidle functions in modules John Stultz
2020-04-15  2:57 ` Paul E. McKenney
2020-04-15  3:47   ` John Stultz
2020-04-15 13:12     ` Paul E. McKenney
2020-04-15 12:53 ` Steven Rostedt
2020-04-15 19:56   ` John Stultz
2020-04-15 20:14     ` Steven Rostedt
2020-04-15 20:17       ` John Stultz
2020-04-15 20:41         ` Steven Rostedt [this message]
2020-04-15 21:02           ` John Stultz
2020-04-15 21:49             ` Steven Rostedt
2020-04-15 22:04               ` Paul E. McKenney
2020-04-15 22:42                 ` Peter Zijlstra
2020-04-15 22:53                   ` Steven Rostedt
2020-04-15 22:53                   ` Paul E. McKenney
2020-04-15 22:51                 ` Steven Rostedt
2020-04-15 22:54                   ` Paul E. McKenney
2020-04-16  0:06                   ` John Stultz
2020-04-16  0:48                     ` Steven Rostedt
2020-04-16  1:02                       ` Bjorn Andersson
2020-04-16  1:24                         ` Steven Rostedt
2020-04-16  2:17                       ` John Stultz
2020-04-15 22:07               ` John Stultz
2020-04-15 22:40       ` Peter Zijlstra

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