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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Chen Guokai <chenguokai17@mails.ucas.ac.cn>,
        "Masami Hiramatsu (Google)" <mhiramat@kernel.org>,
        Liao Chang <liaochang1@huawei.com>,
        Guo Ren <guoren@kernel.org>, Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.15 196/244] csky/kprobe: reclaim insn_slot on kprobe unregistration
Date:   Tue, 23 Aug 2022 10:25:55 +0200
Message-Id: <20220823080105.970987809@linuxfoundation.org>
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From: Liao Chang <liaochang1@huawei.com>

[ Upstream commit a2310c74d418deca0f1d749c45f1f43162510f51 ]

On kprobe registration kernel allocate one insn_slot for new kprobe,
but it forget to reclaim the insn_slot on unregistration, leading to a
potential leakage.

Reported-by: Chen Guokai <chenguokai17@mails.ucas.ac.cn>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Liao Chang <liaochang1@huawei.com>
Signed-off-by: Guo Ren <guoren@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/csky/kernel/probes/kprobes.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/csky/kernel/probes/kprobes.c b/arch/csky/kernel/probes/kprobes.c
index 4045894d9280..584ed9f36290 100644
--- a/arch/csky/kernel/probes/kprobes.c
+++ b/arch/csky/kernel/probes/kprobes.c
@@ -124,6 +124,10 @@ void __kprobes arch_disarm_kprobe(struct kprobe *p)
 
 void __kprobes arch_remove_kprobe(struct kprobe *p)
 {
+	if (p->ainsn.api.insn) {
+		free_insn_slot(p->ainsn.api.insn, 0);
+		p->ainsn.api.insn = NULL;
+	}
 }
 
 static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
-- 
2.35.1