On 1/11/21 4:48 AM, Sedat Dilek wrote:
Hi BPF maintainers and Mashiro, Debian started to use CONFIG_DEBUG_INFO_BTF=y. My kernel-build fails like this: + info BTFIDS vmlinux + [ != silent_ ] + printf %-7s %s\n BTFIDS vmlinux BTFIDS vmlinux + ./tools/bpf/resolve_btfids/resolve_btfids vmlinux FAILED: load BTF from vmlinux: Invalid argument The root cause is my selfmade LLVM toolchain has no BPF support.
linux build should depend on LLVM toolchain unless you use LLVM to build kernel.
$ which llc /home/dileks/src/llvm-toolchain/install/bin/llc $ llc --version LLVM (http://llvm.org/ ): LLVM version 11.0.1 Optimized build. Default target: x86_64-unknown-linux-gnu Host CPU: sandybridge Registered Targets: x86 - 32-bit X86: Pentium-Pro and above x86-64 - 64-bit X86: EM64T and AMD64 Debian's llc-11 shows me BPF support is built-in. I see the breakag approx. 3 hours after the start of my kernel-build - in the stage "vmlinux". After 2 faulures in my build (2x 3 hours of build-time) I have still no finished Linux v5.11-rc3 kernel. This is a bit frustrating.
You mean "BTFIDS vmlinux" takes more than 3 hours here? Maybe a bug in resolve_btfids due to somehow different ELF format resolve_btfids need to handle?
What about doing pre-checks - means before doing a single line of compilation - to check for: 1. Required binaries 2. Required support of whatever feature in compiler, linker, toolchain etc. Recently, I fell over depmod binary not found in my PATH - in one of the last steps (modfinal) of the kernel build. Any ideas to improve the situation? ( ...and please no RTFM, see links below. ) Thanks. Regards, - Sedat - [0] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/scripts/link-vmlinux.sh#n144 [1] https://salsa.debian.org/kernel-team/linux/-/commit/929891281c61ce4403ddd869664c949692644a2f [2] https://www.kernel.org/doc/html/latest/bpf/bpf_devel_QA.html?highlight=pahole#llvm [3] https://www.kernel.org/doc/html/latest/bpf/btf.html?highlight=pahole#btf-generation
