On Tue, Dec 15, 2020 at 10:20 AM Kamal Mostafa kamal@canonical.com wrote:
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 cSuch 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 directoryThis 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") Cc: stable@vger.kernel.org # 5.7+ Signed-off-by: Kamal Mostafa kamal@canonical.com
Applied to bpf tree, thanks. This conflicted with a67079b03165 ("selftests/bpf: fix bpf_testmod.ko recompilation logic"), I resolved the conflict and capitalized "Cannot" in the error message.
[v2] moves the check to right after the VMLINUX_BTF definition.
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 542768f5195b..7ba631f495f7 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
-- 2.17.1