From 4abc2dbd882254f0083504c30e83ac10ae4818b2 Mon Sep 17 00:00:00 2001 From: Kamal Mostafa Date: Tue, 15 Dec 2020 10:20:10 -0800 Subject: [PATCH] selftests/bpf: Clarify build error if no vmlinux commit 1a3449c19407a28f7019a887cdf0d6ba2444751a upstream. If Makefile cannot find any of the vmlinux's in its VMLINUX_BTF_PATHS list, it tries to run btftool incorrectly, with VMLINUX_BTF unset: bpftool btf dump file $(VMLINUX_BTF) format c Such that the keyword 'format' is misinterpreted as the path to vmlinux. The resulting build error message is fairly cryptic: GEN vmlinux.h Error: failed to load BTF from format: No such file or directory This patch makes the failure reason clearer by yielding this instead: Makefile:...: *** Cannot find a vmlinux for VMLINUX_BTF at any of "{paths}". Stop. Fixes: acbd06206bbb ("selftests/bpf: Add vmlinux.h selftest exercising tracing of syscalls") Signed-off-by: Kamal Mostafa Signed-off-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20201215182011.15755-1-kamal@canonical.com Signed-off-by: Greg Kroah-Hartman --- tools/testing/selftests/bpf/Makefile | 3 +++ 1 file changed, 3 insertions(+) diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index 136df8c10281..9359377aeb35 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -146,6 +146,9 @@ VMLINUX_BTF_PATHS ?= $(if $(O),$(O)/vmlinux) \ /sys/kernel/btf/vmlinux \ /boot/vmlinux-$(shell uname -r) VMLINUX_BTF ?= $(abspath $(firstword $(wildcard $(VMLINUX_BTF_PATHS)))) +ifeq ($(VMLINUX_BTF),) +$(error Cannot find a vmlinux for VMLINUX_BTF at any of "$(VMLINUX_BTF_PATHS)") +endif DEFAULT_BPFTOOL := $(SCRATCH_DIR)/sbin/bpftool