Re: [PATCH bpf-next 1/2] bpf: Fix memleak due to fentry attach failure

[Song Liu <song@xxxxxxxxxx>]

On Tue, May 9, 2023 at 7:39 PM Yafang Shao <laoar.shao@xxxxxxxxx> wrote:
>
> On Wed, May 10, 2023 at 1:41 AM Song Liu <song@xxxxxxxxxx> wrote:
[...]
> > > +static void bpf_tramp_image_free(struct bpf_tramp_image *im)
> > > +{
> > > +       bpf_image_ksym_del(&im->ksym);
> > > +       bpf_jit_free_exec(im->image);
> > > +       bpf_jit_uncharge_modmem(PAGE_SIZE);
> > > +       percpu_ref_exit(&im->pcref);
> > > +       kfree(im);
> > > +}
> >
> > Can we share some of this function with __bpf_tramp_image_put_deferred?
> >
>
> It seems we can introduce a generic helper as follows,
>   static void __bpf_tramp_image_free(struct bpf_tramp_image *im)
>   {
>       bpf_image_ksym_del(&im->ksym);
>       bpf_jit_free_exec(im->image);
>       bpf_jit_uncharge_modmem(PAGE_SIZE);
>       percpu_ref_exit(&im->pcref);
>   }
>
> And then use it in both bpf_tramp_image_free() and
> __bpf_tramp_image_put_deferred().
> WDYT?

How about we also use kfree_rcu() in bpf_tramp_image_free()?

Thanks,
Song