From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758162Ab2IEOck (ORCPT ); Wed, 5 Sep 2012 10:32:40 -0400 Received: from mail7.hitachi.co.jp ([133.145.228.42]:37627 "EHLO mail7.hitachi.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756963Ab2IEOcg (ORCPT ); Wed, 5 Sep 2012 10:32:36 -0400 X-AuditID: b753bd60-91b5cba000007c38-97-50476282792a X-AuditID: b753bd60-91b5cba000007c38-97-50476282792a From: Masami Hiramatsu Subject: [PATCH -tip 2/4] [BUGFIX] kprobes/x86: Fix kprobes to collectly handle IP on ftrace To: Steven Rostedt , linux-kernel@vger.kernel.org Cc: "H. Peter Anvin" , Peter Zijlstra , Frederic Weisbecker , Thomas Gleixner , Ingo Molnar , Andrew Morton , yrl.pp-manager.tt@hitachi.com, Masami Hiramatsu , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Steven Rostedt Date: Wed, 05 Sep 2012 23:31:12 +0900 Message-ID: <20120905143112.10329.72069.stgit@localhost.localdomain> In-Reply-To: <20120905143045.10329.64502.stgit@localhost.localdomain> References: <20120905143045.10329.64502.stgit@localhost.localdomain> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Brightmail-Tracker: AAAAAA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Current kprobe_ftrace_handler expects regs->ip == ip, but it is incorrect (originally on x86-64). Actually, ftrace handler sets regs->ip = ip + MCOUNT_INSN_SIZE. kprobe_ftrace_handler must take care for that. Signed-off-by: Masami Hiramatsu Cc: Thomas Gleixner Cc: Ingo Molnar Cc: "H. Peter Anvin" Cc: Steven Rostedt --- arch/x86/kernel/kprobes.c | 9 ++++++--- 1 files changed, 6 insertions(+), 3 deletions(-) diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c index 47ae102..f49f60c 100644 --- a/arch/x86/kernel/kprobes.c +++ b/arch/x86/kernel/kprobes.c @@ -1072,7 +1072,8 @@ void __kprobes kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, if (kprobe_running()) { kprobes_inc_nmissed_count(p); } else { - regs->ip += sizeof(kprobe_opcode_t); + /* Kprobe handler expects regs->ip = ip + 1 as breakpoint hit */ + regs->ip = ip + sizeof(kprobe_opcode_t); __this_cpu_write(current_kprobe, p); kcb->kprobe_status = KPROBE_HIT_ACTIVE; @@ -1080,13 +1081,15 @@ void __kprobes kprobe_ftrace_handler(unsigned long ip, unsigned long parent_ip, p->pre_handler(p, regs); if (unlikely(p->post_handler)) { - /* Emulate singlestep as if there is a 5byte nop */ + /* + * Emulate singlestep (and also recover regs->ip) + * as if there is a 5byte nop + */ regs->ip = ip + MCOUNT_INSN_SIZE; kcb->kprobe_status = KPROBE_HIT_SSDONE; p->post_handler(p, regs, 0); } __this_cpu_write(current_kprobe, NULL); - regs->ip = ip; /* Recover for next callback */ } end: local_irq_restore(flags);