[PATCH AUTOSEL 5.10 23/31] csky/kprobe: reclaim insn_slot on kprobe unregistration

From: Sasha Levin
Date: Sun Aug 14 2022 - 11:50:31 EST


From: Liao Chang <liaochang1@xxxxxxxxxx>

[ 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@xxxxxxxxxxxxxxxx>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
Signed-off-by: Liao Chang <liaochang1@xxxxxxxxxx>
Signed-off-by: Guo Ren <guoren@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
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 556b9ba61ec0..79272dde72db 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