Date: Fri, 3 Apr 2009 10:48:54 +0530
From: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
To: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>, Jim Keniston <jkenisto@us.ibm.com>,
       LKML <linux-kernel@vger.kernel.org>,
       systemtap-ml <systemtap@sources.redhat.com>, kvm@vger.kernel.org,
       Andi Kleen <andi@firstfloor.org>,
       Andrew Morton <akpm@linux-foundation.org>,
       Arnaldo Carvalho de Melo <acme@redhat.com>,
       Steven Rostedt <rostedt@goodmis.org>,
       Frederic Weisbecker <fweisbec@gmail.com>
Subject: Re: [PATCH -tip 4/6 V4] x86: kprobes checks safeness of insertion
	address.
Message-ID: <20090403051854.GA4846@in.ibm.com>
Reply-To: ananth@in.ibm.com
References: <49D4F4E9.2030809@redhat.com>
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On Thu, Apr 02, 2009 at 01:24:57PM -0400, Masami Hiramatsu wrote:
 
> +/* Recover original instruction */
> +static int recover_probed_instruction(kprobe_opcode_t *buf, unsigned long addr)
> +{
> +	struct kprobe *kp;
> +	kp = get_kprobe((void *)addr);
> +	if (!kp)
> +		return -EINVAL;
> +
> +	/* Don't use p->ainsn.insn; which will be modified by fix_riprel */
> +	memcpy(buf, kp->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
> +	buf[0] = kp->opcode;
> +	return 0;
> +}
> +
> +/* Dummy buffers for lookup_symbol_attrs */
> +static char __dummy_buf[KSYM_NAME_LEN];
> +
> +/* Check whether the address can be probed */
> +static int __kprobes can_probe(unsigned long paddr)

A better description would've been "Check if paddr is at an instruction
boundary". Otherwise looks good.

Ananth
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