csky/kprobe: reclaim insn_slot on kprobe unregistration

[ 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>

diff --git a/arch/csky/kernel/probes/kprobes.c b/arch/csky/kernel/probes/kprobes.c
index 556b9ba61ec066be610d894071923a07d661b1f7..79272dde72db30567a045afa492eb4611c5afbec 100644 (file)
--- 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)