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")
Cc: sta...@vger.kernel.org # 5.7+
Signed-off-by: Kamal Mostafa <ka...@canonical.com>
---
[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
