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

[Jisheng Zhang]

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 at 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 at mails.ucas.ac.cn>
> > Signed-off-by: Liao Chang <liaochang1 at huawei.com>

Reviewed-by: Jisheng Zhang <jszhang at 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 at 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/