Thank you for your answer. What I'm ultimately trying to do is: Use aya-rs to watch egress on a network interface and notify userspace through a map (for certain IPs only). In my actual use case, the userspace is supposed to do more complex stuff but for testing I simply logged the receival of a message through the BPF map on the console. And that is what I expect to happen and which does happen as long as CONFIG_TRACING/CONFIG_FTRACE are active. If not, I simply never receive any messages on any map. I've also tried this using an XDP program which sends a message every time it sees a packet. And while the program seemed to be working(since it did block certain traffic), I never saw any data in the map when those configs were disabled. Also, I'm giving you two configs(tracing and ftrace) since the other one seems to get y-selected automatically if one of them is active. On Tue, May 10, 2022 at 2:00 AM Andrii Nakryiko <andrii.nakryiko@xxxxxxxxx> wrote: > > On Tue, May 3, 2022 at 2:40 AM Michael Zimmermann > <sigmaepsilon92@xxxxxxxxx> wrote: > > > > Hi, > > > > I'm using a kernel which has TRACING and FTRACE disabled and it looks > > like BPF programs are unable to communicate with usespace. > > I've reproduced this on aarch64 and x86_64 with both aya-rs's XDP > > sample and bcc's "tc_perf_event.py" sample. bcc's sample uses > > BPF_PERF_OUTPUT instead of maps though. > > > > Everything seems to run and work correctly, but there's no data being > > send to userspace resulting in no log output. > > Is that expected or am I running into a weird bug here? > > > > You probably need to provide few more details on what you are trying > to do, what you expect to happen and what's actually happening. As it > is it's hard to provide any useful help. > > > Thanks > > Michael
