2024-12-09 18:01 UTC+0100 ~ Simone Magnani <simone.magnani@xxxxxxxxxxxxx> > On 09/12/24 16:20, Quentin Monnet wrote: >> Looking again at the probe itself, does the second instruction serve any >> practical purpose here? Don't you just need to test the BPF_JMP32_A? >> >> Looks good otherwise, thank you! >> >> Reviewed-by: Quentin Monnet <qmo@xxxxxxxxxx> > > I wanted to keep probes similar to the previous ones (especially v3 > and v2), despite we never check their return codes. This means > having as 4th instruction `BPF_MOV64_IMM(BPF_REG_0, 1)`. However, > to do so, I also need the 2nd instruction, otherwise I'd hit an > `Invalid Argument` error while calling `bpf_prog_load()`: I think > that would be due to the fact that no execution paths would > execute that instruction otherwise. Right, that's what I missed. > > An alternative approach less consistent with the others would be: > > struct bpf_insn insns[3] = { > BPF_MOV64_IMM(BPF_REG_0, 0), > BPF_JMP32_A(0), > BPF_EXIT_INSN() > }; > > Please let me know if you have any further questions, need > additional information, or if I could improve the patch. No it's all good to me in that case, thank you! Quentin