From: "Paul E. McKenney" <paulmck@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>,
Ingo Molnar <mingo@kernel.org>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Uladzislau Rezki <urezki@gmail.com>,
LKML <linux-kernel@vger.kernel.org>, RCU <rcu@vger.kernel.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Andrew Morton <akpm@linux-foundation.org>,
Daniel Axtens <dja@axtens.net>,
Frederic Weisbecker <frederic@kernel.org>,
Neeraj Upadhyay <neeraju@codeaurora.org>,
Joel Fernandes <joel@joelfernandes.org>,
Michal Hocko <mhocko@suse.com>,
"Theodore Y . Ts'o" <tytso@mit.edu>,
Oleksiy Avramchenko <oleksiy.avramchenko@sonymobile.com>
Subject: Re: [PATCH] kprobes: Fix to delay the kprobes jump optimization
Date: Fri, 19 Feb 2021 11:47:44 -0800 [thread overview]
Message-ID: <20210219194744.GA2743@paulmck-ThinkPad-P72> (raw)
In-Reply-To: <20210219143607.3cdf9ed8@gandalf.local.home>
On Fri, Feb 19, 2021 at 02:36:07PM -0500, Steven Rostedt wrote:
> On Thu, 18 Feb 2021 23:29:23 +0900
> Masami Hiramatsu <mhiramat@kernel.org> wrote:
>
> > Commit 36dadef23fcc ("kprobes: Init kprobes in early_initcall")
> > moved the kprobe setup in early_initcall(), which includes kprobe
> > jump optimization.
> > The kprobes jump optimizer involves synchronize_rcu_tasks() which
> > depends on the ksoftirqd and rcu_spawn_tasks_*(). However, since
> > those are setup in core_initcall(), kprobes jump optimizer can not
> > run at the early_initcall().
> >
> > To avoid this issue, make the kprobe optimization disabled in the
> > early_initcall() and enables it in subsys_initcall().
> >
> > Note that non-optimized kprobes is still available after
> > early_initcall(). Only jump optimization is delayed.
> >
> > Fixes: 36dadef23fcc ("kprobes: Init kprobes in early_initcall")
> > Reported-by: Paul E. McKenney <paulmck@kernel.org>
> > Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
> > Cc: stable@vger.kernel.org
> > ---
>
> I pulled this into my queue to be tested, and when that completes
> (hopefully without failure), I'll add this to my pull request for the
> current merge window (which I still need to send).
Thank you, Steve!
Could you please add the following Reported-by tags?
Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reported-by: Uladzislau Rezki <urezki@gmail.com>
Sebastian first noticed the problem, and Uladzislau figured out
how softirqs were involved.
Thanx, Paul
next prev parent reply other threads:[~2021-02-19 19:48 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-18 14:29 [PATCH] kprobes: Fix to delay the kprobes jump optimization Masami Hiramatsu
2021-02-18 15:15 ` Paul E. McKenney
2021-02-19 8:17 ` Sebastian Andrzej Siewior
2021-02-19 10:49 ` Uladzislau Rezki
2021-02-19 10:57 ` Sebastian Andrzej Siewior
2021-02-19 11:13 ` Uladzislau Rezki
2021-02-19 11:17 ` Sebastian Andrzej Siewior
2021-02-19 11:23 ` Uladzislau Rezki
2021-02-19 11:27 ` Uladzislau Rezki
2021-02-19 18:18 ` Paul E. McKenney
2021-02-19 18:33 ` Paul E. McKenney
2021-02-19 19:34 ` Paul E. McKenney
2021-02-19 20:02 ` Steven Rostedt
2021-02-19 21:22 ` Paul E. McKenney
2021-02-22 10:21 ` Sebastian Andrzej Siewior
2021-02-22 12:54 ` Uladzislau Rezki
2021-02-22 15:09 ` Paul E. McKenney
2021-02-22 17:16 ` Uladzislau Rezki
2021-02-22 18:16 ` Paul E. McKenney
2021-02-22 19:07 ` Uladzislau Rezki
2021-02-22 21:32 ` Paul E. McKenney
2021-02-19 19:14 ` Steven Rostedt
2021-02-19 19:45 ` Paul E. McKenney
2021-02-19 20:04 ` Paul E. McKenney
2021-02-22 10:04 ` Sebastian Andrzej Siewior
2021-02-19 19:36 ` Steven Rostedt
2021-02-19 19:47 ` Paul E. McKenney [this message]
2021-02-19 19:58 ` Steven Rostedt
2021-02-19 20:04 ` Paul E. McKenney
2021-02-22 12:06 ` Masami Hiramatsu
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