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

From: "liaochang (A)" <liaochang1@huawei.com>
To: Guo Ren <guoren@kernel.org>
Cc: Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Masami Hiramatsu <mhiramat@kernel.org>,
	Steven Rostedt <rostedt@goodmis.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Naveen Rao <naveen.n.rao@linux.vnet.ibm.com>,
	<jszhang@kernel.org>,
	linux-riscv <linux-riscv@lists.infradead.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2] riscv/kprobe: reclaim insn_slot on kprobe unregistration
Date: Wed, 25 May 2022 15:59:14 +0800	[thread overview]
Message-ID: <cd9a856b-ed8a-88f1-da69-4fb628c28f34@huawei.com> (raw)
In-Reply-To: <CAJF2gTS9_1D+K-ok2vxQpbq6B7zxv1K-t8cfcu1hFjF=7a5yxQ@mail.gmail.com>


在 2022/5/25 14:23, Guo Ren 写道:
> On Wed, May 25, 2022 at 9:46 AM Liao Chang <liaochang1@huawei.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@mails.ucas.ac.cn>
>> Signed-off-by: Liao Chang <liaochang1@huawei.com>
>> ---
>> 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;
>> +       }
> Thx reviewed-by: Guo Ren <guoren@kernel.org>
> 
> You also could give a fixup patch to csky, thx:
> 
> 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;
> +       }
>  }

Sure, I will, thanks.
> 
>  static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
> 
>>  }
>>
>>  static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
>> --
>> 2.17.1
>>
> 
> 

-- 
BR,
Liao, Chang

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