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Date:   Wed, 25 May 2022 21:33:39 +0800
From:   Jisheng Zhang <jszhang@kernel.org>
To:     Guo Ren <guoren@kernel.org>
Cc:     Liao Chang <liaochang1@huawei.com>,
        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>,
        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
Message-ID: <Yo4wM8qvD/xTfRK1@xhacker>
References: <20220525014424.20717-1-liaochang1@huawei.com>
 <CAJF2gTS9_1D+K-ok2vxQpbq6B7zxv1K-t8cfcu1hFjF=7a5yxQ@mail.gmail.com>
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On Wed, May 25, 2022 at 02:23:50PM +0800, Guo Ren wrote:
> 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>

Reviewed-by: Jisheng Zhang <jszhang@kernel.org>
> > ---
> > 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;
> +       }
>  }
> 
>  static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
> 
> >  }
> >
> >  static void __kprobes save_previous_kprobe(struct kprobe_ctlblk *kcb)
> > --
> > 2.17.1
> >
> 
> 
> -- 
> Best Regards
>  Guo Ren
> 
> ML: https://lore.kernel.org/linux-csky/