Question related to ( commit 9f691549f76d "bpf: fix struct htab_elem layout" )

[Etienne Martineau]

Hi,

I've been staring at this commit for some time and I wonder what were the
symptoms when the issue was reproduced?
  "The bug was discovered by manual code analysis and reproducible
    only with explicit udelay() in lookup_elem_raw()."

I tried various stress test + timing combinations in lookup_elem_raw() but no
luck.

I believe that one of our production boxes ran into that issue lately with a GPF
in the area of htab_map_lookup_elem(). The crash was seen on an outdated
4.9 stable.

Please CC me as I'm not on the list.

thanks in advance,
Etienne