linux-kernel - [PATCH] kprobes/x86: opt: free optinsn cache when range check fails

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Date:	Mon, 28 Jul 2014 20:20:19 +0800
From:	Wang Nan <wangnan0@...wei.com>
To:	Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>,
	Ingo Molnar <mingo@...hat.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Andi Kleen <ak@...ux.intel.com>,
	Pei Feiyue <peifeiyue@...wei.com>
CC:	<x86@...nel.org>, <linux-kernel@...r.kernel.org>,
	<wangnan0@...wei.com>
Subject: [PATCH] kprobes/x86: opt: free optinsn cache when range check fails

This patch frees optinsn slot when range check error to prevent memory
leaks. Before this patch, cache entry in kprobe_insn_cache won't be
freed if kprobe optimizing fails due to range check failure.

Signed-off-by: Wang Nan <wangnan0@...wei.com>
---
 arch/x86/kernel/kprobes/opt.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/kprobes/opt.c b/arch/x86/kernel/kprobes/opt.c
index f304773..f1314d0 100644
--- a/arch/x86/kernel/kprobes/opt.c
+++ b/arch/x86/kernel/kprobes/opt.c
@@ -338,8 +338,10 @@ int arch_prepare_optimized_kprobe(struct optimized_kprobe *op)
 	 * a relative jump.
 	 */
 	rel = (long)op->optinsn.insn - (long)op->kp.addr + RELATIVEJUMP_SIZE;
-	if (abs(rel) > 0x7fffffff)
+	if (abs(rel) > 0x7fffffff) {
+		__arch_remove_optimized_kprobe(op, 0);
 		return -ERANGE;
+	}
 
 	buf = (u8 *)op->optinsn.insn;
 
-- 
1.8.4

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