Kernel build fails on debian/build/tools-perarch/tools/bpf/bpftool/vmlinux

[Bryan Apperson]

I've been attempting to build both the hwe-edge and lowlatency-hwe-next kernels from source. Both fail on bpftool not being present, though `debian/build/tools-perarch/tools/bpf/bpftool/vmlinux.h` is there.

```
make[1]: Leaving directory '/home/ubuntu/build-linux/linux-hwe-6.5-6.5.0/debian/build/tools-perarch/tools/perf'
mv /home/ubuntu/build-linux/linux-hwe-6.5-6.5.0/debian/build/tools-perarch/tools/bpf/bpftool/vmlinux /home/ubuntu/build-linux/linux-hwe-6.5-6.5.0/debian/build/tools-perarch/vmlinux
mv: cannot stat '/home/ubuntu/build-linux/linux-hwe-6.5-6.5.0/debian/build/tools-perarch/tools/bpf/bpftool/vmlinux': No such file or directory
make: *** [debian/rules.d/2-binary-arch.mk:713: /home/ubuntu/build-linux/linux-hwe-6.5-6.5.0/debian/stamps/stamp-build-perarch] Error 1
```

I've installed the related version of libbpf1 and libbpf-devel, but still seeing this.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Johannes Unger (ju93)]

Building 6.8.0-7 was possible. Building 6.8.0-9 fails - but I changed a few things:
added LLVM=1 and removed it later on (then debain/rules clean 'ed),
installed lib*-dev based on "Auto-detecting system features" output,
KBUILD_BUILD_TIMESTAMP='2024-02-13'
CC='ccache cc'

[Sergey Galtsev (sam-j811)]

is there a workaround?

[Jonas Juffinger (jonasjuffinger)]

I tried building 6.1.81 on Ubuntu 22.04 and got the same error message.

[Jason Youzwak (veganjay)]

I experienced a similar issue building 6.5.0-25 on Ubuntu 22.04.

I followed the steps in the "Build Your Own Kernel" post: https://wiki.ubuntu.com/Kernel/BuildYourOwnKernel

Specifically, the error occurs after I ran the build step with the parameters:

fakeroot debian/rules binary-headers binary-generic binary-perarch

I tried the LLVM and CC tricks mentioned in the previous post, but it did not help.

[Jason Youzwak (veganjay)]

Follow-up from my previous comment. The build appears to fail if I try to run it twice without running "clean" in between.

In other words, to successfully build, I ran:

fakeroot debian/rules clean
fakeroot debian/rules binary-headers binary-generic binary-perarch

The drawback is it rebuilds everything (which is about 45 minutes on my machine).