Re: [PATCH] arm64: bpf: Fix branch offset in JIT

[Ilias Apalodimas]

On Mon, Sep 14, 2020 at 10:47:33AM -0700, Xi Wang wrote:
> On Mon, Sep 14, 2020 at 10:03 AM Ilias Apalodimas
> <ilias.apalodimas@xxxxxxxxxx> wrote:
> > Naresh from Linaro reported it during his tests on 5.8-rc1 as well [1].
> > I've included both Jiri and him on the v2 as reporters.
> >
> > [1] https://lkml.org/lkml/2020/8/11/58
> 
> I'm curious what you think of Luke's earlier patch to this bug:

We've briefly discussed this approach with Yauheni while coming up with the 
posted patch.
I think that contructing the array correctly in the first place is better. 
Right now it might only be used in bpf2a64_offset() and bpf_prog_fill_jited_linfo()
but if we fixup the values on the fly in there, everyone that intends to use the
offset for any reason will have to account for the missing instruction.

Cheers
/Ilias
> 
> https://lore.kernel.org/bpf/CANoWswkaj1HysW3BxBMG9_nd48fm0MxM5egdtmHU6YsEc_GUtQ@xxxxxxxxxxxxxx/T/#m4335b4005da0d60059ba96920fcaaecf2637042a