Re: [PATCH v2] selftests/bpf: clarify build error if no vmlinux
From: Andrii Nakryiko <hidden>
Date: 2020-12-16 18:07:43
Also in:
bpf, linux-kselftest, lkml, stable
On Tue, Dec 15, 2020 at 10:20 AM Kamal Mostafa [off-list ref] 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 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: stable@vger.kernel.org # 5.7+
Signed-off-by: Kamal Mostafa <redacted>
---
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.
quoted hunk ↗ jump to hunk
[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