On Tue, Sep 10, 2024 at 8:18 AM Yonghong Song <yonghong.song@xxxxxxxxx> wrote: > > > On 9/10/24 7:44 AM, Dave Thaler wrote: > > Yonghong Song wrote: > > [...] > >> In verifier, we have > >> /* [R,W]x div 0 -> 0 */ > >> /* [R,W]x mod 0 -> [R,W]x */ > >> > >> What the value for > >> Rx_a sdiv Rx_b -> ? > >> where Rx_a = INT64_MIN and Rx_b = -1? > >> > >> Should we just do > >> INT64_MIN sdiv -1 -> -1 > >> or some other values? > > What happens for BPF_NEG INT64_MIN? > > Right. This is equivalent to INT64_MIN/-1. Indeed, we need check and protect for this case as well. why? what's wrong with bpf_neg -1 ?
