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From: Peter Zijlstra <a.p.zijlstra@chello.nl>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: LKML <linux-kernel@vger.kernel.org>,
	Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>,
	Frederic Weisbecker <fweisbec@gmail.com>,
	Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@elte.hu>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [RFC][PATCH] kprobes: Add separate preempt_disabling for kprobes
Date: Thu, 30 Jun 2011 23:56:37 +0200	[thread overview]
Message-ID: <1309470997.12449.614.camel@twins> (raw)
In-Reply-To: <1309449117.26417.90.camel@gandalf.stny.rr.com>

On Thu, 2011-06-30 at 11:51 -0400, Steven Rostedt wrote:
> 
> To solve this, I've added a per_cpu variable called
> kprobe_preempt_disabled, that is set by the kprobe code. If it is set,
> the preempt_schedule() will not preempt the code.

Damn this is ugly. Can we step back and see if we can make the
requirement for kprobe to disable preemption go away?

Why does it have to do that anyway? Isn't it keeping enough per-task
state to allow preemption over the single step?



  parent reply	other threads:[~2011-06-30 21:57 UTC|newest]

Thread overview: 27+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-06-30 13:23 [BUG] kprobes crashing because of preempt count Steven Rostedt
2011-06-30 15:51 ` [RFC][PATCH] kprobes: Add separate preempt_disabling for kprobes Steven Rostedt
2011-06-30 16:14   ` Frederic Weisbecker
2011-06-30 16:46     ` Steven Rostedt
2011-06-30 19:40   ` Jason Baron
2011-06-30 19:42     ` Steven Rostedt
2011-06-30 21:56   ` Peter Zijlstra [this message]
2011-07-01  1:22     ` Masami Hiramatsu
2011-07-01  1:38       ` Steven Rostedt
2011-07-01  1:52         ` Masami Hiramatsu
2011-07-01  5:09   ` Masami Hiramatsu
2011-07-01 11:13     ` Masami Hiramatsu
2011-07-01 12:54       ` Steven Rostedt
2011-07-01 12:19     ` Steven Rostedt
2011-07-01 13:15       ` Masami Hiramatsu
2011-07-01 13:14         ` [RFC PATCH -tip ] [BUGFIX] x86: Remove preempt disabling from kprobes Masami Hiramatsu
2011-07-01 13:43           ` Steven Rostedt
2011-07-01 13:53             ` Steven Rostedt
2011-07-03  2:05               ` Masami Hiramatsu
2011-07-02  6:09           ` Ananth N Mavinakayanahalli
2011-07-01  1:12 ` [BUG] kprobes crashing because of preempt count Masami Hiramatsu
2011-07-01  1:33   ` Steven Rostedt
2011-07-01  2:23     ` Masami Hiramatsu
2011-07-01 11:36   ` Ananth N Mavinakayanahalli
2011-07-01 12:01     ` Masami Hiramatsu
2011-07-01 13:03       ` Ananth N Mavinakayanahalli
2011-07-01 13:19         ` Steven Rostedt

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