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

[Jesper Dangaard Brouer]

On Mon, 14 Sep 2020 15:01:15 +0100 Will Deacon <will@xxxxxxxxxx> wrote:

> Hi Ilias,
> 
> On Mon, Sep 14, 2020 at 04:23:50PM +0300, Ilias Apalodimas wrote:
> > On Mon, Sep 14, 2020 at 03:35:04PM +0300, Ilias Apalodimas wrote:  
> > > On Mon, Sep 14, 2020 at 01:20:43PM +0100, Will Deacon wrote:  
> > > > On Mon, Sep 14, 2020 at 11:36:21AM +0300, Ilias Apalodimas wrote:  
> > > > > Running the eBPF test_verifier leads to random errors looking like this:  
> 
> [...]
> > >   
> > Any suggestion on any Fixes I should apply? The original code was 'correct' and
> > broke only when bounded loops and their self-tests were introduced.  
> 
> Ouch, that's pretty bad as it means nobody is regression testing BPF on
> arm64 with mainline. Damn.

Yes, it unfortunately seems that upstream is lacking BPF regression
testing for ARM64 :-(

This bug surfaced when Red Hat QA tested our kernel backports, on
different archs.

-- 
Best regards,
  Jesper Dangaard Brouer
  MSc.CS, Principal Kernel Engineer at Red Hat
  LinkedIn: http://www.linkedin.com/in/brouer