csky/kprobe: reclaim insn_slot on kprobe unregistration

Liao Chang · guoren83 · commit a2310c74d418 · 2022-07-22T21:36:14.000-04:00
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 &lt;chenguokai17@mails.ucas.ac.cn&gt;
Reviewed-by: Masami Hiramatsu (Google) &lt;mhiramat@kernel.org&gt;
Signed-off-by: Liao Chang &lt;liaochang1@huawei.com&gt;
Signed-off-by: Guo Ren &lt;guoren@kernel.org&gt;
diff --git 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)

Original file line number	Diff line number	Diff line change
`@@ -124,6 +124,10 @@ void __kprobes arch_disarm_kprobe(struct kprobe *p)`
`124`	`124`
`125`	`125`	`void __kprobes arch_remove_kprobe(struct kprobe *p)`
`126`	`126`	`{`
	`127`	`+ if (p->ainsn.api.insn) {`
	`128`	`+ free_insn_slot(p->ainsn.api.insn, 0);`
	`129`	`+ p->ainsn.api.insn = NULL;`
	`130`	`+ }`
`127`	`131`	`}`
`128`	`132`
`129`	`133`	`static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)`