2022-05-26 00:04:21

by Liao, Chang

Subject: [PATCH v2] riscv/kprobe: reclaim insn_slot on kprobe unregistration

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 <[email protected]>
Signed-off-by: Liao Chang <[email protected]>
---
v2:
Add Reported-by tag

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 e6e950b7cf32..f12eb1fbb52c 100644
--- a/arch/riscv/kernel/probes/kprobes.c
+++ b/arch/riscv/kernel/probes/kprobes.c
@@ -110,6 +110,10 @@ 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)
--
2.17.1

2022-05-28 07:36:01

by Masami Hiramatsu

Subject: Re: [PATCH v2] riscv/kprobe: reclaim insn_slot on kprobe unregistration

On Wed, 25 May 2022 09:44:24 +0800
Liao Chang <[email protected]> wrote:

> 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 <[email protected]>
> Signed-off-by: Liao Chang <[email protected]>

Looks good to me.

Fixes: c22b0bcb1dd0 ("riscv: Add kprobes supported")
Cc: [email protected]
Reviewed-by: Masami Hiramatsu (Google) <[email protected]>

Thank you,


> ---
> v2:
> Add Reported-by tag
>
> 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 e6e950b7cf32..f12eb1fbb52c 100644
> --- a/arch/riscv/kernel/probes/kprobes.c
> +++ b/arch/riscv/kernel/probes/kprobes.c
> @@ -110,6 +110,10 @@ 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)
> --
> 2.17.1
>


--
Masami Hiramatsu (Google) <[email protected]>