[tip:perf/urgent] kprobes/x86: Free 'optinsn' cache when range check fails

[tip-bot for Wang Nan]

Commit-ID:  256aae5eac6d328067d1a986a7c5df6f19bdc8b4
Gitweb:     http://git.kernel.org/tip/256aae5eac6d328067d1a986a7c5df6f19bdc8b4
Author:     Wang Nan <wangnan0@xxxxxxxxxx>
AuthorDate: Mon, 28 Jul 2014 20:20:19 +0800
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Wed, 27 Aug 2014 20:24:32 +0200

kprobes/x86: Free 'optinsn' cache when range check fails

This patch frees the 'optinsn' slot when we get a 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@xxxxxxxxxx>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Cc: Pei Feiyue <peifeiyue@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/1406550019-70935-1-git-send-email-wangnan0@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 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;
 
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