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From: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
To: Abhishek Sagar <sagar.abhishek@gmail.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
	jkenisto@us.ibm.com, Masami Hiramatsu <mhiramat@redhat.com>,
	Ingo Molnar <mingo@elte.hu>
Subject: Re: [PATCH 0/3][RFC] x86: Catch stray non-kprobe breakpoints
Date: Tue, 29 Jan 2008 11:32:04 +0530	[thread overview]
Message-ID: <20080129060203.GA15576@in.ibm.com> (raw)
In-Reply-To: <479C4A28.3020705@gmail.com>

On Sun, Jan 27, 2008 at 02:38:56PM +0530, Abhishek Sagar wrote:
> Greetings,
> 
> Non kprobe breakpoints in the kernel might lie inside the .kprobes.text section. Such breakpoints can easily be identified by in_kprobes_functions and can be caught early. These are problematic and a warning should be emitted to discourage them (in any rare case, if they actually occur).

Why? As Masami indicated in an earlier reply, the annotation is to
prevent *only* kprobes.
 
> For this, a check can route the trap handling of such breakpoints away from kprobe_handler (which ends up calling even more functions marked as __kprobes) from inside kprobe_exceptions_notify.

Well.. we pass on control of a !kprobe breakpoint to the kernel. This is
exactly what permits debuggers like xmon to work fine now. I don't see
any harm in such breakpoints being handled autonomously without any sort
of kprobe influence.

Ananth

  reply	other threads:[~2008-01-29  6:01 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-01-27  9:08 Abhishek Sagar
2008-01-29  6:02 ` Ananth N Mavinakayanahalli [this message]
2008-01-29 10:40   ` Abhishek Sagar
2008-01-29 13:18     ` Ananth N Mavinakayanahalli
2008-01-29 17:24       ` Abhishek Sagar
2008-01-29 15:13     ` Masami Hiramatsu
2008-01-29 18:08       ` Abhishek Sagar
2008-01-29 19:29         ` Masami Hiramatsu
2008-01-30  4:07           ` Ananth N Mavinakayanahalli

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