linux-kernel - Re: [PATCH] riscv/kprobe: reclaim insn_slot on kprobe unregistration

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Message-ID: <6c692ace-9902-e11f-21c2-ef464be4d3c6@huawei.com>
Date:   Wed, 25 May 2022 09:24:15 +0800
From:   "liaochang (A)" <liaochang1@...wei.com>
To:     Jisheng Zhang <jszhang@...nel.org>, Guo Ren <guoren@...nel.org>
CC:     <paul.walmsley@...ive.com>, <palmer@...belt.com>,
        <aou@...s.berkeley.edu>, <mhiramat@...nel.org>,
        <rostedt@...dmis.org>, <peterz@...radead.org>,
        <naveen.n.rao@...ux.vnet.ibm.com>,
        <linux-riscv@...ts.infradead.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] riscv/kprobe: reclaim insn_slot on kprobe unregistration

在 2022/5/24 23:12, Jisheng Zhang 写道:
> On Mon, May 23, 2022 at 09:51:24AM +0800, Liao Chang 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.
> 
> + Guo Ren
> 
> Nice catch! I think csky needs the fix as well.
> 
>>
>> This bug reported by Chen Guokai <chenguokai17@...ls.ucas.ac.cn>.
> 
> This needs a "Reported-by: ..." tag

Thanks for comment.

> 
>>
>> Signed-off-by: Liao Chang <liaochang1@...wei.com>
>> ---
>>  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
>>
>>
>> _______________________________________________
>> linux-riscv mailing list
>> linux-riscv@...ts.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-riscv
> .

-- 
BR,
Liao, Chang

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