[PATCH] riscv: kprobes: free insn slot in arch_remove_kprobe() to avoid memory leak

[Xiaofeng Yuan]

When a kprobe is removed, arch_remove_kprobe() does not free the
instruction slot allocated by arch_prepare_kprobe(). This causes
a memory leak every time a kprobe is unregistered.

Other architectures such as arm64, x86, and powerpc all free
the slot in their arch_remove_kprobe() implementations. Add
the missing free_insn_slot() call for RISC-V.

Signed-off-by: Xiaofeng Yuan <yuanxiaofeng@xxxxxxxxxxxxxxxxxx>
---
 arch/riscv/kernel/probes/kprobes.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/riscv/kernel/probes/kprobes.c b/arch/riscv/kernel/probes/kprobes.c
index 9e2afabf94..a76eab2972 100644
--- a/arch/riscv/kernel/probes/kprobes.c
+++ b/arch/riscv/kernel/probes/kprobes.c
@@ -128,6 +128,10 @@ 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)
-- 
2.43.0