linux-kernel - [PATCH 1/2] uprobes/x86: Change __skip_sstep() to actually skip the whole insn

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Date:	Sun, 30 Dec 2012 16:47:19 +0100
From:	Oleg Nesterov <oleg@...hat.com>
To:	Ingo Molnar <mingo@...e.hu>, Peter Zijlstra <peterz@...radead.org>,
	Srikar Dronamraju <srikar@...ux.vnet.ibm.com>
Cc:	Ananth N Mavinakayanahalli <ananth@...ibm.com>,
	Anton Arapov <anton@...hat.com>,
	Frank Eigler <fche@...hat.com>,
	Josh Stone <jistone@...hat.com>,
	"Suzuki K. Poulose" <suzuki@...ibm.com>,
	linux-kernel@...r.kernel.org
Subject: [PATCH 1/2] uprobes/x86: Change __skip_sstep() to actually skip
	the whole insn

__skip_sstep() doesn't update regs->ip. Currently this is correct
but only "by accident" and it doesn't skip the whole insn. Change
it to advance ->ip by the length of the detected 0x66*0x90 sequence.

Signed-off-by: Oleg Nesterov <oleg@...hat.com>
---
 arch/x86/kernel/uprobes.c |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
index c71025b..4e33a35 100644
--- a/arch/x86/kernel/uprobes.c
+++ b/arch/x86/kernel/uprobes.c
@@ -680,8 +680,11 @@ static bool __skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
 		if (auprobe->insn[i] == 0x66)
 			continue;
 
-		if (auprobe->insn[i] == 0x90)
+		if (auprobe->insn[i] == 0x90) {
+			regs->ip = uprobe_get_swbp_addr(regs);
+			regs->ip += i + 1;
 			return true;
+		}
 
 		break;
 	}
-- 
1.5.5.1

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