From: Masami Hiramatsu <mhiramat@kernel.org>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-kernel@vger.kernel.org,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Masami Hiramatsu <mhiramat@kernel.org>
Subject: Re: [RFC][PATCH 3/5] kprobes: Take get_online_cpus() before taking jump_label_lock()
Date: Thu, 18 May 2017 02:50:36 +0900 [thread overview]
Message-ID: <20170518025036.5bd900cdab5c3998b3d32c4d@kernel.org> (raw)
In-Reply-To: <20170512172450.127400191@goodmis.org>
On Fri, 12 May 2017 13:15:47 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:
> From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
>
> jump_label_lock() is taken under get_online_cpus(). Make sure that kprobes
> follows suit.
BTW, register_aggr_kprobe() is called under kprobe_mutex locked.
Is that OK?
Thank you,
>
> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> ---
> kernel/kprobes.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/kprobes.c b/kernel/kprobes.c
> index d733479a10ee..57cf73aef488 100644
> --- a/kernel/kprobes.c
> +++ b/kernel/kprobes.c
> @@ -1294,13 +1294,13 @@ static int register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p)
> int ret = 0;
> struct kprobe *ap = orig_p;
>
> - /* For preparing optimization, jump_label_text_reserved() is called */
> - jump_label_lock();
> /*
> * Get online CPUs to avoid text_mutex deadlock.with stop machine,
> * which is invoked by unoptimize_kprobe() in add_new_kprobe()
> */
> get_online_cpus();
> + /* For preparing optimization, jump_label_text_reserved() is called */
> + jump_label_lock();
> mutex_lock(&text_mutex);
>
> if (!kprobe_aggrprobe(orig_p)) {
> @@ -1348,8 +1348,8 @@ static int register_aggr_kprobe(struct kprobe *orig_p, struct kprobe *p)
>
> out:
> mutex_unlock(&text_mutex);
> - put_online_cpus();
> jump_label_unlock();
> + put_online_cpus();
>
> if (ret == 0 && kprobe_disabled(ap) && !kprobe_disabled(p)) {
> ap->flags &= ~KPROBE_FLAG_DISABLED;
> --
> 2.10.2
>
>
--
Masami Hiramatsu <mhiramat@kernel.org>
next prev parent reply other threads:[~2017-05-17 17:50 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-12 17:15 [RFC][PATCH 0/5] perf/tracing/cpuhotplug: Fix locking order Steven Rostedt
2017-05-12 17:15 ` [RFC][PATCH 1/5] tracing: Make sure RCU is watching before calling a stack trace Steven Rostedt
2017-05-12 18:25 ` Paul E. McKenney
2017-05-12 18:36 ` Steven Rostedt
2017-05-12 18:50 ` Paul E. McKenney
2017-05-12 20:05 ` Steven Rostedt
2017-05-12 20:31 ` Paul E. McKenney
2017-05-17 16:46 ` Steven Rostedt
2017-05-12 17:15 ` [RFC][PATCH 2/5] cpu-hotplug: Allow get_online_cpus() to nest Steven Rostedt
2017-05-12 18:35 ` Paul E. McKenney
2017-05-12 18:40 ` Steven Rostedt
2017-05-12 18:52 ` Paul E. McKenney
2017-05-12 22:15 ` Thomas Gleixner
2017-05-13 0:23 ` Steven Rostedt
2017-05-12 17:15 ` [RFC][PATCH 3/5] kprobes: Take get_online_cpus() before taking jump_label_lock() Steven Rostedt
2017-05-12 18:39 ` Paul E. McKenney
2017-05-12 18:44 ` Steven Rostedt
2017-05-17 17:50 ` Masami Hiramatsu [this message]
2017-05-12 17:15 ` [RFC][PATCH 4/5] tracepoints: Grab get_online_cpus() before taking tracepoints_mutex Steven Rostedt
2017-05-12 17:15 ` [RFC][PATCH 5/5] perf: Grab event_mutex before taking get_online_cpus() Steven Rostedt
2017-05-12 18:13 ` [RFC][PATCH 0/5] perf/tracing/cpuhotplug: Fix locking order Paul E. McKenney
2017-05-12 19:49 ` Peter Zijlstra
2017-05-12 20:14 ` Steven Rostedt
2017-05-12 21:34 ` Steven Rostedt
2017-05-13 13:40 ` Paul E. McKenney
2017-05-15 9:03 ` Peter Zijlstra
2017-05-15 18:40 ` Paul E. McKenney
2017-05-16 8:19 ` Peter Zijlstra
2017-05-16 12:46 ` Paul E. McKenney
2017-05-16 14:27 ` Paul E. McKenney
2017-05-17 10:40 ` Peter Zijlstra
2017-05-17 14:55 ` Paul E. McKenney
2017-05-18 3:58 ` Paul E. McKenney
2017-05-15 19:06 ` Steven Rostedt
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