On Fri, Jul 23, 2021 at 7:17 PM Vincent Li <vincent.mc.li@xxxxxxxxx> wrote: > > > Hi BPF experts, > > I have a cilium PR https://github.com/cilium/cilium/pull/16916 that > failed to pass verifier in kernel 4.19, the error is like: > > level=warning msg="Prog section '2/7' rejected: Argument list too long > (7)!" subsys=datapath-loader > level=warning msg=" - Type: 3" subsys=datapath-loader > level=warning msg=" - Attach Type: 0" subsys=datapath-loader > level=warning msg=" - Instructions: 4578 (482 over limit)" > subsys=datapath-loader > level=warning msg=" - License: GPL" subsys=datapath-loader > level=warning subsys=datapath-loader > level=warning msg="Verifier analysis:" subsys=datapath-loader > level=warning subsys=datapath-loader > level=warning msg="Error filling program arrays!" subsys=datapath-loader > level=warning msg="Unable to load program" subsys=datapath-loader > > then I tried to run the PR locally in my dev machine with custom upstream > kernel version, I narrowed the issue down to between upstream kernel > version 5.7 and 5.8, in 5.7, it failed with: I further narrow it down to between 5.7 and 5.8-rc1 release, but still no clue which commits in 5.8-rc1 resolved the issue > > level=warning msg="processed 50 insns (limit 1000000) max_states_per_insn > 0 total_states 1 peak_states 1 mark_read 1" subsys=datapath-loader > level=warning subsys=datapath-loader > level=warning msg="Log buffer too small to dump verifier log 16777215 > bytes (9 tries)!" subsys=datapath-loader > level=warning msg="Error filling program arrays!" subsys=datapath-loader > level=warning msg="Unable to load program" subsys=datapath-loader > > 5.8 works fine. > > What difference between 5.7 and 5.8 to cause this verifier problem, I > tried to git log v5.7..v5.8 kernel/bpf/verifier, I could not see commits > that would make the difference with my limited BPF knowledge. Any clue > would be appreciated! > > Thanks > > Vincent >
