Speaker
Shung-Hsi Yu
(SUSE)
Description
While safety and performance get most of the credit for BPF's success, a safe and fast program that couldn't do anything interesting would be rather useless. Much of the flexibility that makes BPF programs interesting today (e.g. indexing into a map value at a computed offset, walking packet data, reading a stack array at a variable index) was actually not there at the start.
In this talk, we'll give a thousand-foot overview that goes from the initial tracking of constant/unknown all the way to cnum, covering topics like scalar IDs, sub-register bounds, bounds syncing, as well as value-tracking bugs along the way.
Author
Shung-Hsi Yu
(SUSE)