linux-kernel - Re: [PATCH] csky/kprobe: reclaim insn

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Date:   Fri, 27 May 2022 00:30:06 +0900
From:   Masami Hiramatsu (Google) <mhiramat@...nel.org>
To:     Guo Ren <guoren@...nel.org>, Liao Chang <liaochang1@...wei.com>
Cc:     <guoren@...nel.org>, <rostedt@...dmis.org>, <peterz@...radead.org>,
        <lkp@...el.com>, <naveen.n.rao@...ux.vnet.ibm.com>,
        <jszhang@...nel.org>, <linux-csky@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] csky/kprobe: reclaim insn_slot on kprobe unregistration

On Wed, 25 May 2022 16:02:41 +0800
Liao Chang <liaochang1@...wei.com> 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 <chenguokai17@...ls.ucas.ac.cn>
> Signed-off-by: Liao Chang <liaochang1@...wei.com>

This looks good to me too. I think this should go through csky tree.

Reviewed-by: Masami Hiramatsu (Google) <mhiramat@...nel.org>

Thank you,


> ---
>  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 42920f25e73c..661da54b418f 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)
> -- 
> 2.17.1
> 


-- 
Masami Hiramatsu (Google) <mhiramat@...nel.org>