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From: Ingo Molnar <mingo@kernel.org>
To: Masami Hiramatsu <mhiramat@kernel.org>
Cc: mingo@redhat.com, x86@kernel.org,
	Steven Rostedt <rostedt@goodmis.org>,
	linux-kernel@vger.kernel.org,
	Peter Zijlstra <peterz@infradead.org>,
	Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	"H . Peter Anvin" <hpa@zytor.com>,
	"Paul E . McKenney" <paulmck@linux.vnet.ibm.com>,
	Alexei Starovoitov <ast@kernel.org>,
	Alexei Starovoitov <ast@fb.com>
Subject: Re: [PATCH -tip v3 6/7] kprobes/x86: Remove disable_irq from ftrace-based/optimized kprobe
Date: Thu, 28 Sep 2017 09:25:41 +0200	[thread overview]
Message-ID: <20170928072541.daf7oqj6tkq4vmac@gmail.com> (raw)
In-Reply-To: <150581534039.32348.11331736206004264553.stgit@devbox>


* Masami Hiramatsu <mhiramat@kernel.org> wrote:

> Actually kprobes doesn't need to disable irq if it is
> called from ftrace/jump trampoline code because
> Documentation/kprobes.txt says
> 
> -----
> Probe handlers are run with preemption disabled.  Depending on the
> architecture and optimization state, handlers may also run with
> interrupts disabled (e.g., kretprobe handlers and optimized kprobe
> handlers run without interrupt disabled on x86/x86-64).
> -----
> 
> So let's remove irq disabling from those handlers.

> -	local_irq_save(flags);

The title is talking about disable_irq():

  kprobes/x86: Remove disable_irq from ftrace-based/optimized kprobe

... but the patch is actually using local_irq_save(), which is an entirely 
different thing! You probably wanted to say:

  kprobes/x86: Remove irq disabling from ftrace-based/optimized kprobes

Also note the plural of 'kprobes' when we refer to them as a generic thing.

I fixed the title, but _please_ read changelogs more carefully before sending 
them.

Thanks,

	Ingo

  reply	other threads:[~2017-09-28  7:25 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-09-19  9:58 [PATCH -tip v3 0/7] kprobes/x86: Preempt related enhancements Masami Hiramatsu
2017-09-19  9:59 ` [PATCH -tip v3 1/7] kprobes: Improve smoke test to check preemptible Masami Hiramatsu
2017-09-28 10:52   ` [tip:perf/core] kprobes: Improve smoke test to check preemptibility tip-bot for Masami Hiramatsu
2017-09-19  9:59 ` [PATCH -tip v3 2/7] kprobes/x86: Move get_kprobe_ctlblk in irq-disabled block Masami Hiramatsu
2017-09-28 10:52   ` [tip:perf/core] kprobes/x86: Move the get_kprobe_ctlblk() into " tip-bot for Masami Hiramatsu
2017-09-19 10:00 ` [PATCH -tip v3 3/7] kprobes: Warn if optprobe handler tries to change execution path Masami Hiramatsu
2017-09-28 10:53   ` [tip:perf/core] " tip-bot for Masami Hiramatsu
2017-10-10 17:02   ` [PATCH -tip v3 3/7] " Naveen N. Rao
2017-10-12  5:04     ` Masami Hiramatsu
2017-10-17  8:05       ` Naveen N. Rao
2017-09-19 10:00 ` [PATCH -tip v3 4/7] kprobes/x86: Disable preempt in optprobe Masami Hiramatsu
2017-09-28 10:53   ` [tip:perf/core] kprobes/x86: Disable preemption " tip-bot for Masami Hiramatsu
2017-09-19 10:01 ` [PATCH -tip v3 5/7] kprobes/x86: Disable preempt ftrace-based jprobe Masami Hiramatsu
2017-09-28 10:54   ` [tip:perf/core] kprobes/x86: Disable preemption in ftrace-based jprobes tip-bot for Masami Hiramatsu
2017-09-19 10:02 ` [PATCH -tip v3 6/7] kprobes/x86: Remove disable_irq from ftrace-based/optimized kprobe Masami Hiramatsu
2017-09-28  7:25   ` Ingo Molnar [this message]
2017-09-29  6:48     ` Masami Hiramatsu
2017-09-28 10:54   ` [tip:perf/core] kprobes/x86: Remove IRQ disabling from ftrace-based/optimized kprobes tip-bot for Masami Hiramatsu
2017-09-19 10:03 ` [PATCH -tip v3 7/7] kprobes: Use synchronize_rcu_tasks() for optprobe with CONFIG_PREEMPT Masami Hiramatsu
2017-09-28  7:22   ` Ingo Molnar
2017-09-29  7:29     ` Masami Hiramatsu
2017-09-29  7:37       ` Ingo Molnar
2017-09-29 14:44         ` Masami Hiramatsu
2017-09-29 17:45           ` Ingo Molnar
2017-09-30  5:12             ` Masami Hiramatsu
2017-10-03 23:57       ` Steven Rostedt
2017-10-04 14:01         ` Masami Hiramatsu
2017-09-21 22:00 ` [PATCH -tip v3 0/7] kprobes/x86: Preempt related enhancements Alexei Starovoitov

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