Re: [PATCH bpf-next 6/8] bpf: Add arch_bpf_trampoline_size()

Song Liu
2023-09-21T05:12:16Z

On Wed, Sep 20, 2023 at 5:46 PM Pu Lehui <pulehui@huawei.com> wrote:
>
[...]
> > +int arch_bpf_trampoline_size(const struct btf_func_model *m, u32 flags,
> > + struct bpf_tramp_links *tlinks, void *func_addr)
> > +{
> > + struct bpf_tramp_image im;
> > + struct rv_jit_context ctx;
> > +
> > + ctx.ninsns = 0;
> > + ctx.insns = NULL;
> > + ctx.ro_insns = NULL;
> > + ret = __arch_prepare_bpf_trampoline(&im, m, tlinks, func_addr, flags, &ctx);
> > +
> > + return ret < 0 ? ret : ninsns_rvoff(ctx->ninsns);
> > +}
> > +
> > int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image,
> > void *image_end, const struct btf_func_model *m,
> > u32 flags, struct bpf_tramp_links *tlinks,
> > @@ -1032,14 +1046,8 @@ int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image,
> > int ret;
> > struct rv_jit_context ctx;
> >
> > - ctx.ninsns = 0;
> > - ctx.insns = NULL;
> > - ctx.ro_insns = NULL;
> > - ret = __arch_prepare_bpf_trampoline(im, m, tlinks, func_addr, flags, &ctx);
> > - if (ret < 0)
> > - return ret;
> > -
> > - if (ninsns_rvoff(ret) > (long)image_end - (long)image)
> > + ret = arch_bpf_trampoline_size(im, m, flags, tlinks, func_addr);
>
> Hi Song, there is missing check for negative return values.

Thanks! I will fix it in the next version.

Song

> > + if (ret > (long)image_end - (long)image)
> > return -EFBIG;
> >
> > ctx.ninsns = 0;
> > diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
> > index e6a643f63ebf..8fab4795b497 100644
> > --- a/arch/s390/net/bpf_jit_comp.c
> > +++ b/arch/s390/net/bpf_jit_comp.c
> > @@ -2483,6 +2483,21 @@ static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im,
> > return 0;
> > } …