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Message-ID: <20120905143045.10329.64502.stgit@localhost.localdomain>
Date: Wed, 05 Sep 2012 23:30:46 +0900
From: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
To: Steven Rostedt <rostedt@...dmis.org>, linux-kernel@...r.kernel.org
Cc: "H. Peter Anvin" <hpa@...ux.intel.com>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Frederic Weisbecker <fweisbec@...il.com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...e.hu>,
Andrew Morton <akpm@...ux-foundation.org>,
yrl.pp-manager.tt@...achi.com
Subject: [PATCH -tip 0/4][BUGFIX] Fix ftrace-based kprobes
Hi,
This series of patches fixes some bugs and corrects behaviors
of ftrace and ftrace-based kprobe.
As Fengguang reported at https://lkml.org/lkml/2012/8/24/45
ftrace-based kprobes and -mfentry option caused failures
on kprobe smoke test. This basically comes from the initial
design of ftrace-based kprobe which prohibits jprobe on
ftraced kprobe.
Without -mfentry support, this works well because NO mcount
call is at the first instruction of any function. However,
-mfentry calls it at the first one and it conflicts with
jprobe.
On this series, kprobe allows jprobe even if it is based on
ftrace. For this fix, I need following fixes.
- Make ftrace-handler interface same on x86/x86-64
On x86, ftrace_regs_caller puts a same address on ip and
regs.ip, however those are different on x86-64. I've
modified x86 to fit to x86-64 ABI.
- Fix kprobe ftrace handler for above ABI change
Current kprobe_ftrace_handler expects ip == regs.ip, but
it's not correct on x86-64 (and now on x86 too). This should
be fixed.
- Use regs.ip for return address on ftrace
From Steven, this change is suggested. Thanks!
Thank you,
---
Masami Hiramatsu (3):
[BUGFIX] kprobes/x86: Fix to support jprobes on ftrace-based kprobe
[BUGFIX] kprobes/x86: Fix kprobes to collectly handle IP on ftrace
[BUGFIX] ftrace/x86: Adjust x86 regs.ip as like as x86-64
Steven Rostedt (1):
ftrace/x86-64: Allow to change RIP in handlers
arch/x86/kernel/entry_32.S | 3 +--
arch/x86/kernel/entry_64.S | 4 ++++
arch/x86/kernel/kprobes.c | 43 +++++++++++++++++++++++++++++++------------
kernel/kprobes.c | 3 ---
4 files changed, 36 insertions(+), 17 deletions(-)
--
Masami HIRAMATSU
Software Platform Research Dept. Linux Technology Center
Hitachi, Ltd., Yokohama Research Laboratory
E-mail: masami.hiramatsu.pt@...achi.com
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