CODEWITHSUNDEEP
bpfebpf
Maicake
Maicake

Reputation: 1126

Can't get ebpf program jitted output using bpftool

When I run sudo bpftool prog show I get the following output

39: socket_filter  name bpfprog1  tag e29cda32ba011d7f  gpl
    loaded_at 2019-09-08T14:21:57+0200  uid 1000
    xlated 248B  jited 169B  memlock 4096B  map_ids 30

but If I try to get the program jitted output with the following command

 sudo bpftool prog dump jited tag e29cda32ba011d7f

I get an error message, as reported below:

Error: can't get prog info (3): Bad address

QUESTION: what am I doing wrong? XD

Upvotes: 1

Views: 1131

Answers (1)

Qeole
Qeole

Reputation: 9114

You most certainly use a bpftool version compiled from Linux 4.20 or older, and hit a bug that was fixed in version 5.0. Update bpftool, and dumping programs by tags should work again.

As a side note, I usually use program IDs or pinned path, as I find it more useful to retrieve the program I want. Depending on your use case, tags might make sense, especially if you often load the same programs without changes (so you would be sure to keep the same tags) and do not have them pinned.

Upvotes: 1

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