Date: Tue, 7 Feb 2006 15:25:52 -0500
From: Chuck Ebbert <76306.1226@compuserve.com>
Subject: 2.6.16-rc1-mm5: explanation text for
  kretprobe-kretprobe-booster.patch
To: Andrew Morton <akpm@osdl.org>
Cc: "David S. Miller" <davem@davemloft.net>,
       Ananth N Mavinakayanahalli <ananth@in.ibm.com>,
       Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>,
       Prasanna S Panchamukhi <prasanna@in.ibm.com>,
       linux-kernel <linux-kernel@vger.kernel.org>,
       Masami Hiramatsu <hiramatu@sdl.hitachi.co.jp>
Message-ID: <200602071528_MC3-1-B7DD-D2ED@compuserve.com>
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In kretprobe-kretprobe-booster.patch:

> From: Masami Hiramatsu <hiramatu@sdl.hitachi.co.jp>
>
> What does this do?
>

Here's a description:

In normal operation, kretprobe makes a target function return
to trampoline code. A kprobe (called trampoline_probe) has
been inserted in the trampoline code. When the kernel hits this
kprobe, it calls kretprobe's handler and it returns to the original
return address.

Kretprobe-booster removes the trampoline_probe. It allows the
trampoline code to call kretprobe's handler directly instead of
invoking kprobe. The trampoline code returns to the original return
address.

-- 
Chuck
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