From: Kamal Mostafa kamal@canonical.com
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 kamal@canonical.com Signed-off-by: Andrii Nakryiko andrii@kernel.org Link: https://lore.kernel.org/bpf/20201215182011.15755-1-kamal@canonical.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- tools/testing/selftests/bpf/Makefile | 3 +++ 1 file changed, 3 insertions(+)
--- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -146,6 +146,9 @@ VMLINUX_BTF_PATHS ?= $(if $(O),$(O)/vmli /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