test_kmods/Makefile always pointed KDIR at the kernel source tree root, ignoring O= and KBUILD_OUTPUT. On distro kernels where the source tree has not been built, the Makefile had no fallback and would fail unconditionally.
When O= or KBUILD_OUTPUT is set and points at a prepared kernel build directory (one containing Module.symvers), pass it through so kbuild can locate the correct build infrastructure (scripts, Kconfig, etc.). Note that the module artifacts themselves still land in the M= directory, which is test_kmods/; O= only controls where kbuild finds its build infrastructure. Fall back to /lib/modules/$(uname -r)/build when neither an explicit valid build directory nor an in-tree Module.symvers is present. A selftests-only O= value (one that does not contain Module.symvers, e.g. a private output directory) is intentionally not treated as a kernel build directory. Without this guard, a user invoking "make -C tools/testing/selftests/bpf O=/tmp/out" would have test_kmods try to use /tmp/out as the kernel build dir and fail. The parent bpf/Makefile resolves O= and KBUILD_OUTPUT to absolute paths before invoking the test_kmods sub-make. Without this, $(abspath ...) inside test_kmods/Makefile would resolve relative paths against the sub-make's CWD (test_kmods/) rather than the user's invocation directory. When O= is passed to kbuild, also pass KBUILD_OUTPUT=$(KMOD_O_VALID) explicitly. The parent invocation lifts KBUILD_OUTPUT into MAKEFLAGS as a command-line variable, which would otherwise suppress kbuild's own "KBUILD_OUTPUT := $(O)" assignment and cause it to use the inherited KBUILD_OUTPUT instead of the validated O=. Guard both all and clean against a missing KDIR so the step is silently skipped rather than fatal. Make the parent Makefile's cp conditional so it does not abort when modules were not built. Signed-off-by: Ricardo B. Marlière <[email protected]> --- tools/testing/selftests/bpf/Makefile | 10 +++++---- tools/testing/selftests/bpf/test_kmods/Makefile | 30 ++++++++++++++++++++++--- 2 files changed, 33 insertions(+), 7 deletions(-) diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index 6094fe99b5f6..cc6ee7a2df93 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -296,13 +296,15 @@ $(OUTPUT)/sign-file: ../../../../scripts/sign-file.c # subst() turns the rule into a pattern matching rule $(addprefix test_kmods/,$(subst .ko,%ko,$(TEST_KMODS))): $(VMLINUX_BTF) $(RESOLVE_BTFIDS) $(wildcard test_kmods/Makefile test_kmods/*.[ch]) $(Q)$(RM) test_kmods/*.ko test_kmods/*.mod.o # force re-compilation - $(Q)$(MAKE) $(submake_extras) -C test_kmods \ - RESOLVE_BTFIDS=$(RESOLVE_BTFIDS) \ + $(Q)$(MAKE) $(submake_extras) -C test_kmods \ + $(if $(O),O=$(abspath $(O))) \ + $(if $(KBUILD_OUTPUT),KBUILD_OUTPUT=$(abspath $(KBUILD_OUTPUT)))\ + RESOLVE_BTFIDS=$(RESOLVE_BTFIDS) \ EXTRA_CFLAGS='' EXTRA_LDFLAGS='' $(TEST_KMOD_TARGETS): $(addprefix test_kmods/,$(TEST_KMODS)) $(call msg,MOD,,$@) - $(Q)cp test_kmods/$(@F) $@ + $(Q)$(if $(PERMISSIVE),if [ -f test_kmods/$(@F) ]; then )cp test_kmods/$(@F) $@$(if $(PERMISSIVE),; fi) DEFAULT_BPFTOOL := $(HOST_SCRATCH_DIR)/sbin/bpftool @@ -718,7 +720,7 @@ $(TRUNNER_LIB_OBJS): $(TRUNNER_OUTPUT)/%.o:$(TOOLSDIR)/lib/%.c $(TRUNNER_BINARY)-extras: $(TRUNNER_EXTRA_FILES) | $(TRUNNER_OUTPUT) ifneq ($2:$(OUTPUT),:$(shell pwd)) $$(call msg,EXT-COPY,$(TRUNNER_BINARY),$(TRUNNER_EXTRA_FILES)) - $(Q)rsync -aq $$^ $(TRUNNER_OUTPUT)/ + $(Q)rsync -aq $(if $(PERMISSIVE),--ignore-missing-args) $$^ $(TRUNNER_OUTPUT)/ endif # some X.test.o files have runtime dependencies on Y.bpf.o files diff --git a/tools/testing/selftests/bpf/test_kmods/Makefile b/tools/testing/selftests/bpf/test_kmods/Makefile index 63c4d3f6a12f..031c7454ce65 100644 --- a/tools/testing/selftests/bpf/test_kmods/Makefile +++ b/tools/testing/selftests/bpf/test_kmods/Makefile @@ -1,5 +1,16 @@ TEST_KMOD_DIR := $(realpath $(dir $(abspath $(lastword $(MAKEFILE_LIST))))) -KDIR ?= $(abspath $(TEST_KMOD_DIR)/../../../../..) +SRCTREE_KDIR := $(abspath $(TEST_KMOD_DIR)/../../../../..) +# Honor O=/KBUILD_OUTPUT only if they point at a prepared kernel build +# directory (one containing Module.symvers); otherwise treat the value as a +# selftests-only output directory and fall back to in-tree or distro headers. +# The parent bpf/Makefile resolves O=/KBUILD_OUTPUT to absolute paths before +# invoking this sub-make so relative paths still anchor to the user's +# invocation directory. +KMOD_O := $(or $(O),$(KBUILD_OUTPUT)) +KMOD_O_VALID := $(if $(KMOD_O),$(if $(wildcard $(KMOD_O)/Module.symvers),$(KMOD_O))) +KDIR ?= $(if $(KMOD_O_VALID),$(SRCTREE_KDIR), \ + $(if $(wildcard $(SRCTREE_KDIR)/Module.symvers),$(SRCTREE_KDIR), \ + /lib/modules/$(shell uname -r)/build)) ifeq ($(V),1) Q = @@ -14,8 +25,21 @@ $(foreach m,$(MODULES),$(eval obj-m += $(m:.ko=.o))) CFLAGS_bpf_testmod.o = -I$(src) +# When BPF_STRICT_BUILD != 0, a missing KDIR is fatal (the default). +# When permissive, skip silently. +PERMISSIVE := $(filter 0,$(BPF_STRICT_BUILD)) + all: - $(Q)$(MAKE) -C $(KDIR) M=$(TEST_KMOD_DIR) modules +ifeq ($(PERMISSIVE),) + $(Q)$(MAKE) -C $(KDIR) $(if $(KMOD_O_VALID),O=$(KMOD_O_VALID) KBUILD_OUTPUT=$(KMOD_O_VALID),KBUILD_OUTPUT=) \ + M=$(TEST_KMOD_DIR) modules +else ifneq ("$(wildcard $(KDIR))", "") + $(Q)$(MAKE) -C $(KDIR) $(if $(KMOD_O_VALID),O=$(KMOD_O_VALID) KBUILD_OUTPUT=$(KMOD_O_VALID),KBUILD_OUTPUT=) \ + M=$(TEST_KMOD_DIR) modules +endif clean: - $(Q)$(MAKE) -C $(KDIR) M=$(TEST_KMOD_DIR) clean +ifneq ("$(wildcard $(KDIR))", "") + $(Q)$(MAKE) -C $(KDIR) $(if $(KMOD_O_VALID),O=$(KMOD_O_VALID) KBUILD_OUTPUT=$(KMOD_O_VALID),KBUILD_OUTPUT=) \ + M=$(TEST_KMOD_DIR) clean +endif -- 2.54.0
