[PATCH bpf-next v6 00/11] selftests/bpf: Tolerate partial builds across kernel configs

[PATCH bpf-next v6 00/11] selftests/bpf: Tolerate partial builds across kernel configs

[Ricardo B. Marlière]

Currently the BPF selftests can only be built by using the minimum kernel
configuration defined in tools/testing/selftests/bpf/config*. This poses a
problem in distribution kernels that may have some of the flags disabled or
set as module. For example, we have been running the tests regularly in
openSUSE Tumbleweed [1] [2] but to work around this fact we created a
special package [3] that build the tests against an auxiliary vmlinux with
the BPF Kconfig. We keep a list of known issues that may happen due to,
amongst other things, configuration mismatches [4] [5].

The maintenance of this package is far from ideal, especially for
enterprise kernels. The goal of this series is to enable the common usecase
of running the following in any system:

```sh
make -C tools/testing/selftests install \
     SKIP_TARGETS= \
     TARGETS=bpf \
     BPF_STRICT_BUILD=0 \
     O=/lib/modules/$(uname -r)/build
```

As an example, the following script targeting a minimal config can be used
for testing:

```sh
make defconfig
scripts/config --file .config \
               --enable DEBUG_INFO_DWARF_TOOLCHAIN_DEFAULT \
               --enable DEBUG_INFO_BTF \
               --enable BPF_SYSCALL \
               --enable BPF_JIT
make olddefconfig
make -j$(nproc)
make -j$(nproc) -C tools/testing/selftests install \
     SKIP_TARGETS= \
     TARGETS=bpf \
     BPF_STRICT_BUILD=0
```

This produces a test_progs binary with 583 subtests, against the total of
714. Many of them will still fail or be skipped at runtime due to lack of
symbols, but at least there will be a clear way of building the tests.

[1]: https://openqa.opensuse.org/tests/5811715
[2]: https://openqa.opensuse.org/tests/5811730
[3]: https://src.opensuse.org/rmarliere/kselftests
[4]: https://github.com/openSUSE/kernel-qe/blob/main/kselftests_known_issues.yaml
[5]: https://openqa.opensuse.org/tests/5811730/logfile?filename=run_kselftests-config_mismatches.txt

Assisted-by: {codex,claude}
Tested-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Ricardo B. Marliere <rbm@suse.com>
---
Changes in v6:
- Add --ignore-missing-args to -extras rsync so out-of-tree permissive
  builds do not abort when .ko files are absent (patch 2)
- Remove stale skeleton headers in early-exit paths when .bpf.o is
  missing on incremental builds (patch 3)
- Fix strict-mode skeleton rules: use && before temp file cleanup so
  bpftool failures are not masked by rm -f exit code (patch 3)
- Track test filter selection separately from not_built so -t/-n flags
  are respected for unbuilt tests (patch 7)
- Make TRUNNER_TEST_OBJS order-only only in permissive mode, preserving
  incremental relinking in strict builds (patch 8)
- Reorder: move skip-unbuilt-tests patch before partial-linking patch
  for bisectability
- Link to v5: https://patch.msgid.link/20260415-selftests-bpf_misconfig-v5-0-03d0a52a898a@suse.com

Changes in v5:
- Add BPF_STRICT_BUILD toggle as patch 1 so every subsequent patch
  gates tolerance behind PERMISSIVE from the start, making the series
  bisectable with strict-by-default at every point
- Fix O= commit message; make parent cp conditional (patch 2)
- Tolerate linked skeleton failures (patch 3)
- Skip feature detection for emit_tests (patch 4)
- Clarify bench is all-or-nothing in commit message (patch 8)
- Move stack_mprotect() to testing_helpers.c, drop weak stubs (patch 9)
- Report not-built tests as "SKIP (not built)" in output (patch 10)
- Drop overly broad 2>/dev/null || true from install rsync; rely solely
  on --ignore-missing-args which already handles absent files (patch 11)
- Link to v4: https://patch.msgid.link/20260406-selftests-bpf_misconfig-v4-0-9914f50efdf7@suse.com

Changes in v4:
- Drop the test_kmods kselftest module flow patch: lib.mk gen_mods_dir
  invokes $(MAKE) -C $(TEST_GEN_MODS_DIR) without forwarding
  RESOLVE_BTFIDS, breaking ASAN and GCC BPF CI builds (Makefile.modfinal
  cannot find resolve_btfids in the kbuild output tree)
- Link to v3:
  https://patch.msgid.link/20260406-selftests-bpf_misconfig-v3-0-587a1114263c@suse.com

Changes in v3:
- Split test_kmods patch into two: fix KDIR handling (O= passthrough,
  EXTRA_CFLAGS/EXTRA_LDFLAGS clearing) and wire into lib.mk via
  TEST_GEN_MODS_DIR
- Pass O= through to the kernel module build so artifacts land in the
  output tree, not the source tree
- Clear EXTRA_CFLAGS and EXTRA_LDFLAGS when invoking the kernel build to
  prevent host flags (e.g. -static) leaking into module compilation
- Replace the bespoke test_kmods pattern rule with lib.mk module
  infrastructure (TEST_GEN_MODS_DIR); lib.mk now drives build and clean
  lifecycle
- Make the .ko copy step resilient: emit SKIP instead of failing when a
  module is absent
- Expand the uprobe weak stub comment in bpf_cookie.c to explain why
  noinline is required
- Link to v2:
  https://patch.msgid.link/20260403-selftests-bpf_misconfig-v2-0-f06700380a9d@suse.com

Changes in v2:
- Skip test_kmods build/clean when KDIR directory does not exist
- Use `Module.symvers` instead of `.config` for in-tree detection
- Fix skeleton order-only prereqs commit message
- Guard BTFIDS step when .test.o is absent
- Add `__weak stack_mprotect()` stubs in `bpf_cookie.c` and `iters.c`
- Link to v1:
  https://patch.msgid.link/20260401-selftests-bpf_misconfig-v1-0-3ae42c0af76f@suse.com

To: Alexei Starovoitov <ast@kernel.org>
To: Daniel Borkmann <daniel@iogearbox.net>
To: Andrii Nakryiko <andrii@kernel.org>
To: Martin KaFai Lau <martin.lau@linux.dev>
To: Eduard Zingerman <eddyz87@gmail.com>
To: Kumar Kartikeya Dwivedi <memxor@gmail.com>
To: Song Liu <song@kernel.org>
To: Yonghong Song <yonghong.song@linux.dev>
To: Jiri Olsa <jolsa@kernel.org>
To: Shuah Khan <shuah@kernel.org>
To: Nathan Chancellor <nathan@kernel.org>
To: Nick Desaulniers <nick.desaulniers+lkml@gmail.com>
To: Bill Wendling <morbo@google.com>
To: Justin Stitt <justinstitt@google.com>
Cc: bpf@vger.kernel.org
Cc: linux-kselftest@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: llvm@lists.linux.dev

---
Ricardo B. Marlière (11):
      selftests/bpf: Add BPF_STRICT_BUILD toggle
      selftests/bpf: Fix test_kmods KDIR to honor O= and distro kernels
      selftests/bpf: Tolerate BPF and skeleton generation failures
      selftests/bpf: Avoid rebuilds when running emit_tests
      selftests/bpf: Make skeleton headers order-only prerequisites of .test.d
      selftests/bpf: Tolerate test file compilation failures
      selftests/bpf: Skip tests whose objects were not built
      selftests/bpf: Allow test_progs to link with a partial object set
      selftests/bpf: Tolerate benchmark build failures
      selftests/bpf: Provide weak definitions for cross-test functions
      selftests/bpf: Tolerate missing files during install

 tools/testing/selftests/bpf/Makefile               | 165 ++++++++++++++-------
 .../testing/selftests/bpf/prog_tests/bpf_cookie.c  |  17 ++-
 tools/testing/selftests/bpf/prog_tests/iters.c     |   3 +-
 tools/testing/selftests/bpf/prog_tests/test_lsm.c  |  22 ---
 tools/testing/selftests/bpf/test_kmods/Makefile    |  24 ++-
 tools/testing/selftests/bpf/test_progs.c           |  50 ++++++-
 tools/testing/selftests/bpf/test_progs.h           |   1 +
 tools/testing/selftests/bpf/testing_helpers.c      |  17 +++
 tools/testing/selftests/bpf/testing_helpers.h      |   1 +
 9 files changed, 208 insertions(+), 92 deletions(-)
---
base-commit: 1f5ffc672165ff851063a5fd044b727ab2517ae3
change-id: 20260401-selftests-bpf_misconfig-4c33ef5c56da

Best regards,
--  
Ricardo B. Marlière <rbm@suse.com>

[PATCH bpf-next v6 01/11] selftests/bpf: Add BPF_STRICT_BUILD toggle

[Ricardo B. Marlière]

Add BPF_STRICT_BUILD (default 1) to control whether BPF compilation
failures are fatal. When set to 0, failures are tolerated and skipped
objects are reported, as implemented by subsequent patches in this
series. When set to 1 (the default), the build fails on any error,
preserving the existing behavior for CI and direct builds.

Users can opt in to permissive mode on the command line:

  make -C tools/testing/selftests \
       TARGETS=bpf SKIP_TARGETS= BPF_STRICT_BUILD=0

Suggested-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Ricardo B. Marlière <rbm@suse.com>
---
 tools/testing/selftests/bpf/Makefile | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 78e60040811e..c8ba8ccc2c6d 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -44,6 +44,12 @@ SKIP_LLVM	?=
 SKIP_LIBBFD	?=
 SKIP_CRYPTO	?=
 
+# When BPF_STRICT_BUILD is 1, any BPF object, skeleton, test object, or
+# benchmark compilation failure is fatal. Set to 0 to tolerate failures
+# and continue building the remaining tests.
+BPF_STRICT_BUILD ?= 1
+PERMISSIVE := $(filter 0,$(BPF_STRICT_BUILD))
+
 ifeq ($(srctree),)
 srctree := $(patsubst %/,%,$(dir $(CURDIR)))
 srctree := $(patsubst %/,%,$(dir $(srctree)))

-- 
2.53.0

[PATCH bpf-next v6 02/11] selftests/bpf: Fix test_kmods KDIR to honor O= and distro kernels

[Ricardo B. Marlière]

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, pass it through so kbuild can locate the
correct kernel build directory (Module.symvers, scripts, 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 build
directory nor an in-tree Module.symvers is present.

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 <rbm@suse.com>
---
 tools/testing/selftests/bpf/Makefile            |  4 ++--
 tools/testing/selftests/bpf/test_kmods/Makefile | 24 +++++++++++++++++++++---
 2 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index c8ba8ccc2c6d..52176dc226f1 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -296,7 +296,7 @@ $(addprefix test_kmods/,$(subst .ko,%ko,$(TEST_KMODS))): $(VMLINUX_BTF) $(RESOLV
 
 $(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
@@ -711,7 +711,7 @@ $(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..10f202bd0d8c 100644
--- a/tools/testing/selftests/bpf/test_kmods/Makefile
+++ b/tools/testing/selftests/bpf/test_kmods/Makefile
@@ -1,5 +1,7 @@
 TEST_KMOD_DIR := $(realpath $(dir $(abspath $(lastword $(MAKEFILE_LIST)))))
-KDIR ?= $(abspath $(TEST_KMOD_DIR)/../../../../..)
+SRCTREE_KDIR := $(abspath $(TEST_KMOD_DIR)/../../../../..)
+KMOD_O := $(or $(O),$(KBUILD_OUTPUT))
+KDIR ?= $(if $(KMOD_O),$(SRCTREE_KDIR),$(if $(wildcard $(SRCTREE_KDIR)/Module.symvers),$(SRCTREE_KDIR),/lib/modules/$(shell uname -r)/build))
 
 ifeq ($(V),1)
 Q =
@@ -14,8 +16,24 @@ $(foreach m,$(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 $(KMOD_O),O=$(KMOD_O),KBUILD_OUTPUT=) \
+		M=$(TEST_KMOD_DIR) modules
+else ifneq ("$(wildcard $(KDIR))", "")
+	$(Q)$(MAKE) -C $(KDIR) $(if $(KMOD_O),O=$(KMOD_O),KBUILD_OUTPUT=) \
+		M=$(TEST_KMOD_DIR) modules
+endif
 
 clean:
-	$(Q)$(MAKE) -C $(KDIR) M=$(TEST_KMOD_DIR) clean
+ifeq ($(PERMISSIVE),)
+	$(Q)$(MAKE) -C $(KDIR) $(if $(KMOD_O),O=$(KMOD_O),KBUILD_OUTPUT=) \
+		M=$(TEST_KMOD_DIR) clean
+else ifneq ("$(wildcard $(KDIR))", "")
+	$(Q)$(MAKE) -C $(KDIR) $(if $(KMOD_O),O=$(KMOD_O),KBUILD_OUTPUT=) \
+		M=$(TEST_KMOD_DIR) clean
+endif

-- 
2.53.0

[PATCH bpf-next v6 03/11] selftests/bpf: Tolerate BPF and skeleton generation failures

[Ricardo B. Marlière]

Some BPF programs cannot be built on distro kernels because required BTF
types or features are missing. A single failure currently aborts the
selftests/bpf build.

Make BPF object and skeleton generation best effort: emit SKIP-BPF or
SKIP-SKEL, remove failed outputs so downstream rules can detect absence,
and continue with remaining tests. Apply the same tolerance to linked
skeletons (TRUNNER_BPF_SKELS_LINKED), which depend on multiple .bpf.o files
and would otherwise abort the build when any dependency is missing.

Signed-off-by: Ricardo B. Marlière <rbm@suse.com>
---
 tools/testing/selftests/bpf/Makefile | 108 +++++++++++++++++++++++------------
 1 file changed, 73 insertions(+), 35 deletions(-)

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 52176dc226f1..b23703f2cf89 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -477,22 +477,26 @@ $(OUTPUT)/cgroup_getset_retval_hooks.o: cgroup_getset_retval_hooks.h
 # $4 - binary name
 define CLANG_BPF_BUILD_RULE
 	$(call msg,CLNG-BPF,$4,$2)
-	$(Q)$(CLANG) $3 -O2 $(BPF_TARGET_ENDIAN) -c $1 -mcpu=v3 -o $2
+	$(Q)$(CLANG) $3 -O2 $(BPF_TARGET_ENDIAN) -c $1 -mcpu=v3 -o $2 $(if $(PERMISSIVE),|| \
+		($(RM) $2; printf '  %-12s %s\n' 'SKIP-BPF' '$(notdir $2)' 1>&2))
 endef
 # Similar to CLANG_BPF_BUILD_RULE, but with disabled alu32
 define CLANG_NOALU32_BPF_BUILD_RULE
 	$(call msg,CLNG-BPF,$4,$2)
-	$(Q)$(CLANG) $3 -O2 $(BPF_TARGET_ENDIAN) -c $1 -mcpu=v2 -o $2
+	$(Q)$(CLANG) $3 -O2 $(BPF_TARGET_ENDIAN) -c $1 -mcpu=v2 -o $2 $(if $(PERMISSIVE),|| \
+		($(RM) $2; printf '  %-12s %s\n' 'SKIP-BPF' '$(notdir $2)' 1>&2))
 endef
 # Similar to CLANG_BPF_BUILD_RULE, but with cpu-v4
 define CLANG_CPUV4_BPF_BUILD_RULE
 	$(call msg,CLNG-BPF,$4,$2)
-	$(Q)$(CLANG) $3 -O2 $(BPF_TARGET_ENDIAN) -c $1 -mcpu=v4 -o $2
+	$(Q)$(CLANG) $3 -O2 $(BPF_TARGET_ENDIAN) -c $1 -mcpu=v4 -o $2 $(if $(PERMISSIVE),|| \
+		($(RM) $2; printf '  %-12s %s\n' 'SKIP-BPF' '$(notdir $2)' 1>&2))
 endef
 # Build BPF object using GCC
 define GCC_BPF_BUILD_RULE
 	$(call msg,GCC-BPF,$4,$2)
-	$(Q)$(BPF_GCC) $3 -DBPF_NO_PRESERVE_ACCESS_INDEX -Wno-attributes -O2 -c $1 -o $2
+	$(Q)$(BPF_GCC) $3 -DBPF_NO_PRESERVE_ACCESS_INDEX -Wno-attributes -O2 -c $1 -o $2 $(if $(PERMISSIVE),|| \
+		($(RM) $2; printf '  %-12s %s\n' 'SKIP-BPF' '$(notdir $2)' 1>&2))
 endef
 
 SKEL_BLACKLIST := btf__% test_pinning_invalid.c test_sk_assign.c
@@ -598,47 +602,81 @@ $(TRUNNER_BPF_OBJS): $(TRUNNER_OUTPUT)/%.bpf.o:				\
 					  $$($$<-$2-CFLAGS),$(TRUNNER_BINARY))
 
 $(TRUNNER_BPF_SKELS): %.skel.h: %.bpf.o $(BPFTOOL) | $(TRUNNER_OUTPUT)
-	$$(call msg,GEN-SKEL,$(TRUNNER_BINARY),$$@)
-	$(Q)$$(BPFTOOL) gen object $$(<:.o=.linked1.o) $$<
-	$(Q)$$(BPFTOOL) gen object $$(<:.o=.linked2.o) $$(<:.o=.linked1.o)
-	$(Q)$$(BPFTOOL) gen object $$(<:.o=.linked3.o) $$(<:.o=.linked2.o)
-	$(Q)diff $$(<:.o=.linked2.o) $$(<:.o=.linked3.o)
-	$(Q)$$(BPFTOOL) gen skeleton $$(<:.o=.linked3.o) name $$(notdir $$(<:.bpf.o=)) > $$@
-	$(Q)$$(BPFTOOL) gen subskeleton $$(<:.o=.linked3.o) name $$(notdir $$(<:.bpf.o=)) > $$(@:.skel.h=.subskel.h)
-	$(Q)rm -f $$(<:.o=.linked1.o) $$(<:.o=.linked2.o) $$(<:.o=.linked3.o)
+	$(Q)$(if $(PERMISSIVE),if [ ! -f $$< ]; then			\
+		$$(RM) $$@ $$(@:.skel.h=.subskel.h);			\
+		printf '  %-12s %s\n' 'SKIP-SKEL' '$$(notdir $$@)' 1>&2; \
+		exit 0;							\
+	fi;)								\
+	printf '  %-12s %s\n' 'GEN-SKEL' '[$(TRUNNER_BINARY)] $$(notdir $$@)' 1>&2; \
+	$$(BPFTOOL) gen object $$(<:.o=.linked1.o) $$< &&		\
+	$$(BPFTOOL) gen object $$(<:.o=.linked2.o) $$(<:.o=.linked1.o) && \
+	$$(BPFTOOL) gen object $$(<:.o=.linked3.o) $$(<:.o=.linked2.o) && \
+	diff $$(<:.o=.linked2.o) $$(<:.o=.linked3.o) &&		\
+	$$(BPFTOOL) gen skeleton $$(<:.o=.linked3.o) name $$(notdir $$(<:.bpf.o=)) > $$@ && \
+	$$(BPFTOOL) gen subskeleton $$(<:.o=.linked3.o) name $$(notdir $$(<:.bpf.o=)) > $$(@:.skel.h=.subskel.h) $(if $(PERMISSIVE),|| { \
+		$$(RM) $$@ $$(@:.skel.h=.subskel.h); \
+		printf '  %-12s %s\n' 'SKIP-SKEL' '$$(notdir $$@)' 1>&2; \
+	}) && \
+	rm -f $$(<:.o=.linked1.o) $$(<:.o=.linked2.o) $$(<:.o=.linked3.o)
 
 $(TRUNNER_BPF_LSKELS): %.lskel.h: %.bpf.o $(BPFTOOL) | $(TRUNNER_OUTPUT)
-	$$(call msg,GEN-SKEL,$(TRUNNER_BINARY),$$@)
-	$(Q)$$(BPFTOOL) gen object $$(<:.o=.llinked1.o) $$<
-	$(Q)$$(BPFTOOL) gen object $$(<:.o=.llinked2.o) $$(<:.o=.llinked1.o)
-	$(Q)$$(BPFTOOL) gen object $$(<:.o=.llinked3.o) $$(<:.o=.llinked2.o)
-	$(Q)diff $$(<:.o=.llinked2.o) $$(<:.o=.llinked3.o)
-	$(Q)$$(BPFTOOL) gen skeleton -L $$(<:.o=.llinked3.o) name $$(notdir $$(<:.bpf.o=_lskel)) > $$@
-	$(Q)rm -f $$(<:.o=.llinked1.o) $$(<:.o=.llinked2.o) $$(<:.o=.llinked3.o)
+	$(Q)$(if $(PERMISSIVE),if [ ! -f $$< ]; then			\
+		$$(RM) $$@;						\
+		printf '  %-12s %s\n' 'SKIP-SKEL' '$$(notdir $$@)' 1>&2; \
+		exit 0;							\
+	fi;)								\
+	printf '  %-12s %s\n' 'GEN-SKEL' '[$(TRUNNER_BINARY)] $$(notdir $$@)' 1>&2; \
+	$$(BPFTOOL) gen object $$(<:.o=.llinked1.o) $$< &&		\
+	$$(BPFTOOL) gen object $$(<:.o=.llinked2.o) $$(<:.o=.llinked1.o) && \
+	$$(BPFTOOL) gen object $$(<:.o=.llinked3.o) $$(<:.o=.llinked2.o) && \
+	diff $$(<:.o=.llinked2.o) $$(<:.o=.llinked3.o) &&		\
+	$$(BPFTOOL) gen skeleton -L $$(<:.o=.llinked3.o) name $$(notdir $$(<:.bpf.o=_lskel)) > $$@ $(if $(PERMISSIVE),|| { \
+		$$(RM) $$@; \
+		printf '  %-12s %s\n' 'SKIP-SKEL' '$$(notdir $$@)' 1>&2; \
+	}) && \
+	rm -f $$(<:.o=.llinked1.o) $$(<:.o=.llinked2.o) $$(<:.o=.llinked3.o)
 
 $(TRUNNER_BPF_LSKELS_SIGNED): %.lskel.h: %.bpf.o $(BPFTOOL) | $(TRUNNER_OUTPUT)
-	$$(call msg,GEN-SKEL,$(TRUNNER_BINARY) (signed),$$@)
-	$(Q)$$(BPFTOOL) gen object $$(<:.o=.llinked1.o) $$<
-	$(Q)$$(BPFTOOL) gen object $$(<:.o=.llinked2.o) $$(<:.o=.llinked1.o)
-	$(Q)$$(BPFTOOL) gen object $$(<:.o=.llinked3.o) $$(<:.o=.llinked2.o)
-	$(Q)diff $$(<:.o=.llinked2.o) $$(<:.o=.llinked3.o)
-	$(Q)$$(BPFTOOL) gen skeleton $(LSKEL_SIGN) $$(<:.o=.llinked3.o) name $$(notdir $$(<:.bpf.o=_lskel)) > $$@
-	$(Q)rm -f $$(<:.o=.llinked1.o) $$(<:.o=.llinked2.o) $$(<:.o=.llinked3.o)
+	$(Q)$(if $(PERMISSIVE),if [ ! -f $$< ]; then			\
+		$$(RM) $$@;						\
+		printf '  %-12s %s\n' 'SKIP-SKEL' '$$(notdir $$@)' 1>&2; \
+		exit 0;							\
+	fi;)								\
+	printf '  %-12s %s\n' 'GEN-SKEL' '[$(TRUNNER_BINARY) (signed)] $$(notdir $$@)' 1>&2; \
+	$$(BPFTOOL) gen object $$(<:.o=.llinked1.o) $$< &&		\
+	$$(BPFTOOL) gen object $$(<:.o=.llinked2.o) $$(<:.o=.llinked1.o) && \
+	$$(BPFTOOL) gen object $$(<:.o=.llinked3.o) $$(<:.o=.llinked2.o) && \
+	diff $$(<:.o=.llinked2.o) $$(<:.o=.llinked3.o) &&		\
+	$$(BPFTOOL) gen skeleton $(LSKEL_SIGN) $$(<:.o=.llinked3.o) name $$(notdir $$(<:.bpf.o=_lskel)) > $$@ $(if $(PERMISSIVE),|| { \
+		$$(RM) $$@; \
+		printf '  %-12s %s\n' 'SKIP-SKEL' '$$(notdir $$@)' 1>&2; \
+	}) && \
+	rm -f $$(<:.o=.llinked1.o) $$(<:.o=.llinked2.o) $$(<:.o=.llinked3.o)
 
 $(LINKED_BPF_OBJS): %: $(TRUNNER_OUTPUT)/%
 
 # .SECONDEXPANSION here allows to correctly expand %-deps variables as prerequisites
 .SECONDEXPANSION:
 $(TRUNNER_BPF_SKELS_LINKED): $(TRUNNER_OUTPUT)/%: $$$$(%-deps) $(BPFTOOL) | $(TRUNNER_OUTPUT)
-	$$(call msg,LINK-BPF,$(TRUNNER_BINARY),$$(@:.skel.h=.bpf.o))
-	$(Q)$$(BPFTOOL) gen object $$(@:.skel.h=.linked1.o) $$(addprefix $(TRUNNER_OUTPUT)/,$$($$(@F)-deps))
-	$(Q)$$(BPFTOOL) gen object $$(@:.skel.h=.linked2.o) $$(@:.skel.h=.linked1.o)
-	$(Q)$$(BPFTOOL) gen object $$(@:.skel.h=.linked3.o) $$(@:.skel.h=.linked2.o)
-	$(Q)diff $$(@:.skel.h=.linked2.o) $$(@:.skel.h=.linked3.o)
-	$$(call msg,GEN-SKEL,$(TRUNNER_BINARY),$$@)
-	$(Q)$$(BPFTOOL) gen skeleton $$(@:.skel.h=.linked3.o) name $$(notdir $$(@:.skel.h=)) > $$@
-	$(Q)$$(BPFTOOL) gen subskeleton $$(@:.skel.h=.linked3.o) name $$(notdir $$(@:.skel.h=)) > $$(@:.skel.h=.subskel.h)
-	$(Q)rm -f $$(@:.skel.h=.linked1.o) $$(@:.skel.h=.linked2.o) $$(@:.skel.h=.linked3.o)
+	$(Q)$(if $(PERMISSIVE),for f in $$(addprefix $(TRUNNER_OUTPUT)/,$$($$(@F)-deps)); do \
+		if [ ! -f $$$$f ]; then						\
+			$$(RM) $$@ $$(@:.skel.h=.subskel.h);		\
+			printf '  %-12s %s\n' 'SKIP-SKEL' '$$(notdir $$@)' 1>&2; \
+			exit 0;							\
+		fi;								\
+	done;)									\
+	printf '  %-12s %s\n' 'LINK-BPF' '[$(TRUNNER_BINARY)] $$(notdir $$(@:.skel.h=.bpf.o))' 1>&2; \
+	$$(BPFTOOL) gen object $$(@:.skel.h=.linked1.o) $$(addprefix $(TRUNNER_OUTPUT)/,$$($$(@F)-deps)) && \
+	$$(BPFTOOL) gen object $$(@:.skel.h=.linked2.o) $$(@:.skel.h=.linked1.o) && \
+	$$(BPFTOOL) gen object $$(@:.skel.h=.linked3.o) $$(@:.skel.h=.linked2.o) && \
+	diff $$(@:.skel.h=.linked2.o) $$(@:.skel.h=.linked3.o) &&	\
+	printf '  %-12s %s\n' 'GEN-SKEL' '[$(TRUNNER_BINARY)] $$(notdir $$@)' 1>&2 && \
+	$$(BPFTOOL) gen skeleton $$(@:.skel.h=.linked3.o) name $$(notdir $$(@:.skel.h=)) > $$@ && \
+	$$(BPFTOOL) gen subskeleton $$(@:.skel.h=.linked3.o) name $$(notdir $$(@:.skel.h=)) > $$(@:.skel.h=.subskel.h) $(if $(PERMISSIVE),|| { \
+		$$(RM) $$@ $$(@:.skel.h=.subskel.h);			\
+		printf '  %-12s %s\n' 'SKIP-SKEL' '$$(notdir $$@)' 1>&2; \
+	}) &&									\
+	rm -f $$(@:.skel.h=.linked1.o) $$(@:.skel.h=.linked2.o) $$(@:.skel.h=.linked3.o)
 
 # When the compiler generates a %.d file, only skel basenames (not
 # full paths) are specified as prerequisites for corresponding %.o

-- 
2.53.0

[PATCH bpf-next v6 04/11] selftests/bpf: Avoid rebuilds when running emit_tests

[Ricardo B. Marlière]

emit_tests is used while installing selftests to generate the kselftest
list. Pulling in .d files for this goal can trigger BPF rebuild rules and
mix build output into list generation.

Skip dependency file inclusion for emit_tests, like clean goals, so list
generation stays side-effect free. Also add emit_tests to
NON_CHECK_FEAT_TARGETS so that feature detection is skipped; without this,
Makefile.feature's $(info) output leaks into stdout and corrupts the test
list captured by the top-level selftests Makefile.

Signed-off-by: Ricardo B. Marlière <rbm@suse.com>
---
 tools/testing/selftests/bpf/Makefile | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index b23703f2cf89..7d1e5d6c30ec 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -164,7 +164,7 @@ endef
 
 include ../lib.mk
 
-NON_CHECK_FEAT_TARGETS := clean docs-clean
+NON_CHECK_FEAT_TARGETS := clean docs-clean emit_tests
 CHECK_FEAT := $(filter-out $(NON_CHECK_FEAT_TARGETS),$(or $(MAKECMDGOALS), "none"))
 ifneq ($(CHECK_FEAT),)
 FEATURE_USER := .selftests
@@ -723,7 +723,7 @@ $(TRUNNER_TEST_OBJS:.o=.d): $(TRUNNER_OUTPUT)/%.test.d:			\
 			    $(TRUNNER_BPF_SKELS_LINKED)			\
 			    $$(BPFOBJ) | $(TRUNNER_OUTPUT)
 
-ifeq ($(filter clean docs-clean,$(MAKECMDGOALS)),)
+ifeq ($(filter clean docs-clean emit_tests,$(MAKECMDGOALS)),)
 include $(wildcard $(TRUNNER_TEST_OBJS:.o=.d))
 endif
 

-- 
2.53.0

[PATCH bpf-next v6 05/11] selftests/bpf: Make skeleton headers order-only prerequisites of .test.d

[Ricardo B. Marlière]

The .test.d dependency files are generated by the C preprocessor and list
the headers each test file actually #includes. Skeleton headers appear in
those generated lists, so the .test.o -> .skel.h dependency is already
tracked by the .d file content.

Making skeletons order-only prerequisites of .test.d means that a missing
or skipped skeleton does not prevent .test.d generation, and regenerating a
skeleton does not force .test.d to be recreated. This avoids unnecessary
recompilation and, more importantly, avoids build errors when a skeleton
was intentionally skipped due to a BPF compilation failure.

Signed-off-by: Ricardo B. Marlière <rbm@suse.com>
---
 tools/testing/selftests/bpf/Makefile | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 7d1e5d6c30ec..b3eaa4a93707 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -717,11 +717,11 @@ $(TRUNNER_TEST_OBJS): $(TRUNNER_OUTPUT)/%.test.o:			\
 $(TRUNNER_TEST_OBJS:.o=.d): $(TRUNNER_OUTPUT)/%.test.d:			\
 			    $(TRUNNER_TESTS_DIR)/%.c			\
 			    $(TRUNNER_EXTRA_HDRS)			\
+			    $$(BPFOBJ) | $(TRUNNER_OUTPUT)		\
 			    $(TRUNNER_BPF_SKELS)			\
 			    $(TRUNNER_BPF_LSKELS)			\
 			    $(TRUNNER_BPF_LSKELS_SIGNED)		\
-			    $(TRUNNER_BPF_SKELS_LINKED)			\
-			    $$(BPFOBJ) | $(TRUNNER_OUTPUT)
+			    $(TRUNNER_BPF_SKELS_LINKED)
 
 ifeq ($(filter clean docs-clean emit_tests,$(MAKECMDGOALS)),)
 include $(wildcard $(TRUNNER_TEST_OBJS:.o=.d))

-- 
2.53.0

[PATCH bpf-next v6 06/11] selftests/bpf: Tolerate test file compilation failures

[Ricardo B. Marlière]

Individual test files may fail to compile when headers or kernel features
required by that test are absent. Currently this aborts the entire build.

Make the per-test compilation non-fatal: remove the output object on
failure and print a SKIP-TEST marker to stderr. Guard the BTFIDS
post-processing step so it is skipped when the object file is absent. The
linker step will later ignore absent objects, allowing the remaining tests
to build and run.

Use plain printf and $(Q) instead of $(call msg,...) in the BTFIDS block:
the msg macro expands to @printf which is a make-recipe construct and is
invalid as a shell command inside an if-then-fi body; $(Q) restores echo
suppression at the recipe level where it is meaningful.

Signed-off-by: Ricardo B. Marlière <rbm@suse.com>
---
 tools/testing/selftests/bpf/Makefile | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index b3eaa4a93707..5ad50d3ff2f8 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -708,11 +708,14 @@ $(TRUNNER_TEST_OBJS): $(TRUNNER_OUTPUT)/%.test.o:			\
 		      $(TRUNNER_TESTS_DIR)/%.c				\
 		      | $(TRUNNER_OUTPUT)/%.test.d
 	$$(call msg,TEST-OBJ,$(TRUNNER_BINARY),$$@)
-	$(Q)cd $$(@D) && $$(CC) -I. $$(CFLAGS) -MMD -MT $$@ -c $(CURDIR)/$$< $$(LDLIBS) -o $$(@F)
+	$(Q)cd $$(@D) && $$(CC) -I. $$(CFLAGS) -MMD -MT $$@ -c $(CURDIR)/$$< $$(LDLIBS) -o $$(@F) $(if $(PERMISSIVE),|| \
+		($(RM) $$(@F); printf '  %-12s %s\n' 'SKIP-TEST' '$$(notdir $$@)' 1>&2))
 	$$(if $$(TEST_NEEDS_BTFIDS),						\
-		$$(call msg,BTFIDS,$(TRUNNER_BINARY),$$@)			\
+		$(Q)if [ -f $$@ ]; then						\
+		printf '  %-8s%s %s\n' "BTFIDS" " [$(TRUNNER_BINARY)]" "$$(notdir $$@)"; \
 		$(RESOLVE_BTFIDS) --btf $(TRUNNER_OUTPUT)/btf_data.bpf.o $$@;	\
-		$(RESOLVE_BTFIDS) --patch_btfids $$@.BTF_ids $$@)
+		$(RESOLVE_BTFIDS) --patch_btfids $$@.BTF_ids $$@;		\
+		fi)
 
 $(TRUNNER_TEST_OBJS:.o=.d): $(TRUNNER_OUTPUT)/%.test.d:			\
 			    $(TRUNNER_TESTS_DIR)/%.c			\

-- 
2.53.0

[PATCH bpf-next v6 07/11] selftests/bpf: Skip tests whose objects were not built

[Ricardo B. Marlière]

When both run_test and run_serial_test are NULL (because the corresponding
.test.o was not compiled), mark the test as not built instead of fatally
aborting.

Report these tests as "SKIP (not built)" in per-test output and include
them in the skip count so they remain visible in CI results and JSON
output. The summary line shows the not-built count when nonzero:

  Summary: 50/55 PASSED, 5 SKIPPED (3 not built), 0 FAILED

Tests filtered out by -t/-n remain invisible as before; only genuinely
unbuilt tests are surfaced.

Signed-off-by: Ricardo B. Marlière <rbm@suse.com>
---
 tools/testing/selftests/bpf/test_progs.c | 50 +++++++++++++++++++++++++++-----
 tools/testing/selftests/bpf/test_progs.h |  1 +
 2 files changed, 44 insertions(+), 7 deletions(-)

diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c
index 7fe16b5131b1..f04a579ecd4d 100644
--- a/tools/testing/selftests/bpf/test_progs.c
+++ b/tools/testing/selftests/bpf/test_progs.c
@@ -165,6 +165,8 @@ struct prog_test_def {
 	void (*run_test)(void);
 	void (*run_serial_test)(void);
 	bool should_run;
+	bool not_built;
+	bool selected;
 	bool need_cgroup_cleanup;
 	bool should_tmon;
 };
@@ -372,6 +374,8 @@ static void print_test_result(const struct prog_test_def *test, const struct tes
 	fprintf(env.stdout_saved, "#%-*d %s:", TEST_NUM_WIDTH, test->test_num, test->test_name);
 	if (test_state->error_cnt)
 		fprintf(env.stdout_saved, "FAIL");
+	else if (test->not_built)
+		fprintf(env.stdout_saved, "SKIP (not built)");
 	else if (!skipped_cnt)
 		fprintf(env.stdout_saved, "OK");
 	else if (skipped_cnt == subtests_cnt || !subtests_cnt)
@@ -1700,8 +1704,13 @@ static void calculate_summary_and_print_errors(struct test_env *env)
 	if (env->json)
 		fclose(env->json);
 
-	printf("Summary: %d/%d PASSED, %d SKIPPED, %d FAILED\n",
-	       succ_cnt, sub_succ_cnt, skip_cnt, fail_cnt);
+	if (env->not_built_cnt)
+		printf("Summary: %d/%d PASSED, %d SKIPPED (%d not built), %d FAILED\n",
+		       succ_cnt, sub_succ_cnt, skip_cnt, env->not_built_cnt,
+		       fail_cnt);
+	else
+		printf("Summary: %d/%d PASSED, %d SKIPPED, %d FAILED\n",
+		       succ_cnt, sub_succ_cnt, skip_cnt, fail_cnt);
 
 	env->succ_cnt = succ_cnt;
 	env->sub_succ_cnt = sub_succ_cnt;
@@ -1772,6 +1781,19 @@ static void server_main(void)
 		run_one_test(i);
 	}
 
+	/* mark not-built tests as skipped */
+	for (int i = 0; i < prog_test_cnt; i++) {
+		struct prog_test_def *test = &prog_test_defs[i];
+		struct test_state *state = &test_states[i];
+
+		if (test->not_built && test->selected) {
+			state->tested = true;
+			state->skip_cnt = 1;
+			env.not_built_cnt++;
+			print_test_result(test, state);
+		}
+	}
+
 	/* generate summary */
 	fflush(stderr);
 	fflush(stdout);
@@ -2046,15 +2068,20 @@ int main(int argc, char **argv)
 		struct prog_test_def *test = &prog_test_defs[i];
 
 		test->test_num = i + 1;
-		test->should_run = should_run(&env.test_selector,
-					      test->test_num, test->test_name);
+		test->selected = should_run(&env.test_selector,
+					    test->test_num, test->test_name);
+		test->should_run = test->selected;
 
-		if ((test->run_test == NULL && test->run_serial_test == NULL) ||
-		    (test->run_test != NULL && test->run_serial_test != NULL)) {
+		if (test->run_test && test->run_serial_test) {
 			fprintf(stderr, "Test %d:%s must have either test_%s() or serial_test_%sl() defined.\n",
 				test->test_num, test->test_name, test->test_name, test->test_name);
 			exit(EXIT_ERR_SETUP_INFRA);
 		}
+		if (!test->run_test && !test->run_serial_test) {
+			test->not_built = true;
+			test->should_run = false;
+			continue;
+		}
 		if (test->should_run)
 			test->should_tmon = should_tmon(&env.tmon_selector, test->test_name);
 	}
@@ -2106,9 +2133,18 @@ int main(int argc, char **argv)
 
 	for (i = 0; i < prog_test_cnt; i++) {
 		struct prog_test_def *test = &prog_test_defs[i];
+		struct test_state *state = &test_states[i];
 
-		if (!test->should_run)
+		if (!test->should_run) {
+			if (test->not_built && test->selected &&
+			    !env.get_test_cnt && !env.list_test_names) {
+				state->tested = true;
+				state->skip_cnt = 1;
+				env.not_built_cnt++;
+				print_test_result(test, state);
+			}
 			continue;
+		}
 
 		if (env.get_test_cnt) {
 			env.succ_cnt++;
diff --git a/tools/testing/selftests/bpf/test_progs.h b/tools/testing/selftests/bpf/test_progs.h
index 1a44467f4310..6ee10360e314 100644
--- a/tools/testing/selftests/bpf/test_progs.h
+++ b/tools/testing/selftests/bpf/test_progs.h
@@ -125,6 +125,7 @@ struct test_env {
 	int sub_succ_cnt; /* successful sub-tests */
 	int fail_cnt; /* total failed tests + sub-tests */
 	int skip_cnt; /* skipped tests */
+	int not_built_cnt; /* tests not built */
 
 	int saved_netns_fd;
 	int workers; /* number of worker process */

-- 
2.53.0

[PATCH bpf-next v6 08/11] selftests/bpf: Allow test_progs to link with a partial object set

[Ricardo B. Marlière]

When individual test files are skipped due to compilation failures, their
.test.o files are absent. The linker step currently lists all expected
.test.o files as explicit prerequisites, so make considers any missing one
an error.

Move TRUNNER_TEST_OBJS to the order-only prerequisite list so that their
absence does not prevent linking. Use $(wildcard ...) in the filter
expression passed to the linker so that only the objects that were actually
built are linked in.

Place the wildcard expansion before $^ in the filter to preserve the
original link order: test objects must precede libbpf.a so that GNU ld,
which scans static archives left-to-right, pulls in archive members that
are referenced exclusively by test objects (e.g. ring_buffer__new from
ringbuf.c).

Signed-off-by: Ricardo B. Marlière <rbm@suse.com>
---
 tools/testing/selftests/bpf/Makefile | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 5ad50d3ff2f8..79991dc98ddd 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -758,14 +758,15 @@ endif
 # some X.test.o files have runtime dependencies on Y.bpf.o files
 $(OUTPUT)/$(TRUNNER_BINARY): | $(TRUNNER_BPF_OBJS)
 
-$(OUTPUT)/$(TRUNNER_BINARY): $(TRUNNER_TEST_OBJS)			\
+$(OUTPUT)/$(TRUNNER_BINARY): $(if $(PERMISSIVE),,$(TRUNNER_TEST_OBJS))	\
 			     $(TRUNNER_EXTRA_OBJS) $$(BPFOBJ)		\
 			     $(TRUNNER_LIB_OBJS)			\
 			     $(TRUNNER_BPFTOOL)				\
 			     $(OUTPUT)/veristat				\
-			     | $(TRUNNER_BINARY)-extras
+			     | $(TRUNNER_BINARY)-extras			\
+			     $(if $(PERMISSIVE),$(TRUNNER_TEST_OBJS))
 	$$(call msg,BINARY,,$$@)
-	$(Q)$$(CC) $$(CFLAGS) $$(filter %.a %.o,$$^) $$(LDLIBS) $$(LLVM_LDLIBS) $$(LDFLAGS) $$(LLVM_LDFLAGS) -o $$@
+	$(Q)$$(CC) $$(CFLAGS) $$(filter %.a %.o,$(if $(PERMISSIVE),$$(wildcard $(TRUNNER_TEST_OBJS)),$(TRUNNER_TEST_OBJS)) $$^) $$(LDLIBS) $$(LLVM_LDLIBS) $$(LDFLAGS) $$(LLVM_LDFLAGS) -o $$@
 	$(Q)ln -sf $(if $2,..,.)/tools/build/bpftool/$(USE_BOOTSTRAP)bpftool \
 		   $(OUTPUT)/$(if $2,$2/)bpftool
 

-- 
2.53.0

[PATCH bpf-next v6 09/11] selftests/bpf: Tolerate benchmark build failures

[Ricardo B. Marlière]

Benchmark objects depend on skeletons that may be missing when some BPF
programs fail to build. In that case, benchmark object compilation or final
bench linking should not abort the full selftests/bpf build.

Keep both steps non-fatal, emit SKIP-BENCH or SKIP-LINK, and remove failed
outputs so stale objects or binaries are not reused by later incremental
builds. Note that because bench.c statically references every benchmark via
extern symbols, partial linking is not possible: if any single benchmark
object fails, the entire bench binary is skipped. This is by design -- the
error handler catches all compilation failures including genuine ones, but
those are caught by full-config CI runs.

Signed-off-by: Ricardo B. Marlière <rbm@suse.com>
---
 tools/testing/selftests/bpf/Makefile | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 79991dc98ddd..9e3e0a898e40 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -896,7 +896,8 @@ $(OUTPUT)/test_cpp: test_cpp.cpp $(OUTPUT)/test_core_extern.skel.h $(BPFOBJ)
 # Benchmark runner
 $(OUTPUT)/bench_%.o: benchs/bench_%.c bench.h $(BPFOBJ)
 	$(call msg,CC,,$@)
-	$(Q)$(CC) $(CFLAGS) -O2 -c $(filter %.c,$^) $(LDLIBS) -o $@
+	$(Q)$(CC) $(CFLAGS) -O2 -c $(filter %.c,$^) $(LDLIBS) -o $@ $(if $(PERMISSIVE),|| \
+		($(RM) $@; printf '  %-12s %s\n' 'SKIP-BENCH' '$(notdir $@)' 1>&2))
 $(OUTPUT)/bench_rename.o: $(OUTPUT)/test_overhead.skel.h
 $(OUTPUT)/bench_trigger.o: $(OUTPUT)/trigger_bench.skel.h
 $(OUTPUT)/bench_ringbufs.o: $(OUTPUT)/ringbuf_bench.skel.h \
@@ -939,7 +940,8 @@ $(OUTPUT)/bench: $(OUTPUT)/bench.o \
 		 $(OUTPUT)/usdt_2.o \
 		 #
 	$(call msg,BINARY,,$@)
-	$(Q)$(CC) $(CFLAGS) $(LDFLAGS) $(filter %.a %.o,$^) $(LDLIBS) -o $@
+	$(Q)$(CC) $(CFLAGS) $(LDFLAGS) $(filter %.a %.o,$(if $(PERMISSIVE),$(wildcard $^),$^)) $(LDLIBS) -o $@ $(if $(PERMISSIVE),|| \
+		($(RM) $@; printf '  %-12s %s\n' 'SKIP-LINK' '$(notdir $@) (some benchmarks may have been skipped)' 1>&2))
 
 # This works around GCC warning about snprintf truncating strings like:
 #

-- 
2.53.0

[PATCH bpf-next v6 10/11] selftests/bpf: Provide weak definitions for cross-test functions

[Ricardo B. Marlière]

Some test files reference functions defined in other translation units that
may not be compiled when skeletons are missing. Replace forward
declarations of uprobe_multi_func_{1,2,3}() with weak no-op stubs so the
linker resolves them regardless of which objects are present.

Move stack_mprotect() from test_lsm.c into testing_helpers.c so it is
always available. The previous weak-stub approach returned 0, which would
cause callers expecting -1/EPERM to fail their assertions
deterministically. Having the real implementation in a shared utility
avoids this problem entirely.

Signed-off-by: Ricardo B. Marlière <rbm@suse.com>
---
 .../testing/selftests/bpf/prog_tests/bpf_cookie.c  | 17 +++++++++++------
 tools/testing/selftests/bpf/prog_tests/iters.c     |  3 +--
 tools/testing/selftests/bpf/prog_tests/test_lsm.c  | 22 ----------------------
 tools/testing/selftests/bpf/testing_helpers.c      | 17 +++++++++++++++++
 tools/testing/selftests/bpf/testing_helpers.h      |  1 +
 5 files changed, 30 insertions(+), 30 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c b/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c
index 35adc3f6d443..5a864cd8ad1b 100644
--- a/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c
+++ b/tools/testing/selftests/bpf/prog_tests/bpf_cookie.c
@@ -252,10 +252,17 @@ static void kprobe_multi_attach_api_subtest(void)
 	kprobe_multi__destroy(skel);
 }
 
-/* defined in prog_tests/uprobe_multi_test.c */
-void uprobe_multi_func_1(void);
-void uprobe_multi_func_2(void);
-void uprobe_multi_func_3(void);
+/*
+ * Weak uprobe target stubs. noinline is required because
+ * uprobe_multi_test_run() takes their addresses to configure the BPF
+ * program's attachment points; an inlined function has no stable
+ * address in the binary to probe. The strong definitions in
+ * uprobe_multi_test.c take precedence when that translation unit is
+ * linked.
+ */
+noinline __weak void uprobe_multi_func_1(void) {}
+noinline __weak void uprobe_multi_func_2(void) {}
+noinline __weak void uprobe_multi_func_3(void) {}
 
 static void uprobe_multi_test_run(struct uprobe_multi *skel)
 {
@@ -574,8 +581,6 @@ static void tracing_subtest(struct test_bpf_cookie *skel)
 		close(fmod_ret_fd);
 }
 
-int stack_mprotect(void);
-
 static void lsm_subtest(struct test_bpf_cookie *skel)
 {
 	__u64 cookie;
diff --git a/tools/testing/selftests/bpf/prog_tests/iters.c b/tools/testing/selftests/bpf/prog_tests/iters.c
index a539980a2fbe..7c0b59fdf498 100644
--- a/tools/testing/selftests/bpf/prog_tests/iters.c
+++ b/tools/testing/selftests/bpf/prog_tests/iters.c
@@ -7,6 +7,7 @@
 #include <unistd.h>
 #include <malloc.h>
 #include <stdlib.h>
+#include <linux/compiler.h>
 #include <test_progs.h>
 #include "cgroup_helpers.h"
 
@@ -202,8 +203,6 @@ static void subtest_task_iters(void)
 	iters_task__destroy(skel);
 }
 
-extern int stack_mprotect(void);
-
 static void subtest_css_task_iters(void)
 {
 	struct iters_css_task *skel = NULL;
diff --git a/tools/testing/selftests/bpf/prog_tests/test_lsm.c b/tools/testing/selftests/bpf/prog_tests/test_lsm.c
index bdc4fc06bc5a..d7495efd4a56 100644
--- a/tools/testing/selftests/bpf/prog_tests/test_lsm.c
+++ b/tools/testing/selftests/bpf/prog_tests/test_lsm.c
@@ -5,36 +5,14 @@
  */
 
 #include <test_progs.h>
-#include <sys/mman.h>
 #include <sys/wait.h>
 #include <unistd.h>
-#include <malloc.h>
-#include <stdlib.h>
 
 #include "lsm.skel.h"
 #include "lsm_tailcall.skel.h"
 
 char *CMD_ARGS[] = {"true", NULL};
 
-#define GET_PAGE_ADDR(ADDR, PAGE_SIZE)					\
-	(char *)(((unsigned long) (ADDR + PAGE_SIZE)) & ~(PAGE_SIZE-1))
-
-int stack_mprotect(void)
-{
-	void *buf;
-	long sz;
-	int ret;
-
-	sz = sysconf(_SC_PAGESIZE);
-	if (sz < 0)
-		return sz;
-
-	buf = alloca(sz * 3);
-	ret = mprotect(GET_PAGE_ADDR(buf, sz), sz,
-		       PROT_READ | PROT_WRITE | PROT_EXEC);
-	return ret;
-}
-
 int exec_cmd(int *monitored_pid)
 {
 	int child_pid, child_status;
diff --git a/tools/testing/selftests/bpf/testing_helpers.c b/tools/testing/selftests/bpf/testing_helpers.c
index 6fbe1e995660..3f7ae76c209b 100644
--- a/tools/testing/selftests/bpf/testing_helpers.c
+++ b/tools/testing/selftests/bpf/testing_helpers.c
@@ -5,6 +5,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
+#include <sys/mman.h>
 #include <bpf/bpf.h>
 #include <bpf/libbpf.h>
 #include "disasm.h"
@@ -516,3 +517,19 @@ bool is_jit_enabled(void)
 
 	return enabled;
 }
+
+int stack_mprotect(void)
+{
+	void *buf;
+	long sz;
+	int ret;
+
+	sz = sysconf(_SC_PAGESIZE);
+	if (sz < 0)
+		return sz;
+
+	buf = alloca(sz * 3);
+	ret = mprotect((void *)(((unsigned long)(buf + sz)) & ~(sz - 1)), sz,
+		       PROT_READ | PROT_WRITE | PROT_EXEC);
+	return ret;
+}
diff --git a/tools/testing/selftests/bpf/testing_helpers.h b/tools/testing/selftests/bpf/testing_helpers.h
index 2ca2356a0b58..2edc6fb7fc52 100644
--- a/tools/testing/selftests/bpf/testing_helpers.h
+++ b/tools/testing/selftests/bpf/testing_helpers.h
@@ -59,5 +59,6 @@ struct bpf_insn;
 int get_xlated_program(int fd_prog, struct bpf_insn **buf, __u32 *cnt);
 int testing_prog_flags(void);
 bool is_jit_enabled(void);
+int stack_mprotect(void);
 
 #endif /* __TESTING_HELPERS_H */

-- 
2.53.0

[PATCH bpf-next v6 11/11] selftests/bpf: Tolerate missing files during install

[Ricardo B. Marlière]

With partial builds, some TEST_GEN_FILES entries can be absent at install
time. rsync treats missing source arguments as fatal and aborts kselftest
installation.

Override INSTALL_SINGLE_RULE in selftests/bpf to use --ignore-missing-args,
while keeping the existing bpf-specific INSTALL_RULE extension logic. Also
add --ignore-missing-args to the TEST_INST_SUBDIRS rsync loop so that
subdirectories with no .bpf.o files (e.g. when a test runner flavor was
skipped) do not abort installation.

Note that the INSTALL_SINGLE_RULE override applies globally to all file
categories including static source files (TEST_PROGS, TEST_FILES). These
are version-controlled and should always be present, so the practical risk
is negligible.

Signed-off-by: Ricardo B. Marlière <rbm@suse.com>
---
 tools/testing/selftests/bpf/Makefile | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 9e3e0a898e40..2808387b3d9f 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -974,11 +974,22 @@ EXTRA_CLEAN := $(SCRATCH_DIR) $(HOST_SCRATCH_DIR)			\
 # Delete partially updated (corrupted) files on error
 .DELETE_ON_ERROR:
 
+# When permissive, tell rsync to ignore missing source arguments so that
+# partial builds do not abort installation.
+ifneq ($(PERMISSIVE),)
+override define INSTALL_SINGLE_RULE
+	$(if $(INSTALL_LIST),@mkdir -p $(INSTALL_PATH))
+	$(if $(INSTALL_LIST),rsync -a --copy-unsafe-links --ignore-missing-args $(INSTALL_LIST) $(INSTALL_PATH)/)
+endef
+endif
+
 DEFAULT_INSTALL_RULE := $(INSTALL_RULE)
 override define INSTALL_RULE
 	$(DEFAULT_INSTALL_RULE)
-	@for DIR in $(TEST_INST_SUBDIRS); do		  \
-		mkdir -p $(INSTALL_PATH)/$$DIR;   \
-		rsync -a $(OUTPUT)/$$DIR/*.bpf.o $(INSTALL_PATH)/$$DIR;\
+	@for DIR in $(TEST_INST_SUBDIRS); do				  \
+		mkdir -p $(INSTALL_PATH)/$$DIR;				  \
+		rsync -a $(if $(PERMISSIVE),--ignore-missing-args)	  \
+			$(OUTPUT)/$$DIR/*.bpf.o				  \
+			$(INSTALL_PATH)/$$DIR;				  \
 	done
 endef

-- 
2.53.0

Re: [PATCH bpf-next v6 02/11] selftests/bpf: Fix test_kmods KDIR to honor O= and distro kernels

[sashiko-bot]

Sashiko AI review found 2 potential issue(s):
- [Medium] Relative paths passed via `O=` are incorrectly evaluated from the kernel source root instead of the invocation directory.
- [Medium] The `make clean` target unconditionally fails and aborts the build if the kernel source tree is unconfigured and distro headers are missing.
--

commit 533e8d39cc98f56f3dff4f8c5bff0dcd49fc6ef1
Author: Ricardo B. Marlière <rbm@suse.com>

selftests/bpf: Fix test_kmods KDIR to honor O= and distro kernels

This commit modifies test_kmods/Makefile to honor O= and KBUILD_OUTPUT, and
adds a fallback to /lib/modules/$(uname -r)/build for distro kernels. It also
makes missing KDIR silently skipped when building in permissive mode.

> diff --git a/tools/testing/selftests/bpf/test_kmods/Makefile b/tools/testing/selftests/bpf/test_kmods/Makefile
> index 63c4d3f6a12f6..10f202bd0d8c2 100644
> --- a/tools/testing/selftests/bpf/test_kmods/Makefile
> +++ b/tools/testing/selftests/bpf/test_kmods/Makefile
> @@ -1,5 +1,7 @@
>  TEST_KMOD_DIR := $(realpath $(dir $(abspath $(lastword $(MAKEFILE_LIST)))))
> -KDIR ?= $(abspath $(TEST_KMOD_DIR)/../../../../..)
> +SRCTREE_KDIR := $(abspath $(TEST_KMOD_DIR)/../../../../..)
> +KMOD_O := $(or $(O),$(KBUILD_OUTPUT))

Will this break out-of-tree builds if a user passes a relative path?

If a user builds selftests with a relative O= path (e.g. make O=out), KMOD_O
captures this relative string and passes it unaltered to the kernel build
system via make -C $(KDIR) O=$(KMOD_O).

Because make -C changes the working directory to $(KDIR) before evaluating
O=, the relative path will be evaluated relative to the kernel root rather
than the directory where make was originally invoked.

[ ... ]
> @@ -14,8 +16,24 @@ $(foreach m,$(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 $(KMOD_O),O=$(KMOD_O),KBUILD_OUTPUT=) \
> +		M=$(TEST_KMOD_DIR) modules

[ ... ]

>  clean:
> -	$(Q)$(MAKE) -C $(KDIR) M=$(TEST_KMOD_DIR) clean
> +ifeq ($(PERMISSIVE),)
> +	$(Q)$(MAKE) -C $(KDIR) $(if $(KMOD_O),O=$(KMOD_O),KBUILD_OUTPUT=) \
> +		M=$(TEST_KMOD_DIR) clean

Does this unconditionally abort make clean if the kernel source tree is
unconfigured and distro headers are missing?

If the system lacks installed kernel headers, /lib/modules/$(uname -r)/build
will not exist. In the default strict mode, GNU Make's -C flag will
immediately throw a fatal 'No such file or directory' error and abort the
make clean process.

> +else ifneq ("$(wildcard $(KDIR))", "")
> +	$(Q)$(MAKE) -C $(KDIR) $(if $(KMOD_O),O=$(KMOD_O),KBUILD_OUTPUT=) \
> +		M=$(TEST_KMOD_DIR) clean
> +endif

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260416-selftests-bpf_misconfig-v6-0-7efeab504af1@suse.com?part=2

Re: [PATCH bpf-next v6 08/11] selftests/bpf: Allow test_progs to link with a partial object set

[bot+bpf-ci]

[-- Attachment #1: Type: text/plain, Size: 2154 bytes --]

> diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
> index 5ad50d3ff2f8..79991dc98ddd 100644
> --- a/tools/testing/selftests/bpf/Makefile
> +++ b/tools/testing/selftests/bpf/Makefile

[ ... ]

> -$(OUTPUT)/$(TRUNNER_BINARY): $(TRUNNER_TEST_OBJS)			\
> +$(OUTPUT)/$(TRUNNER_BINARY): $(if $(PERMISSIVE),,$(TRUNNER_TEST_OBJS))	\
>  			     $(TRUNNER_EXTRA_OBJS) $$(BPFOBJ)		\

[ ... ]

> -	$(Q)$$(CC) $$(CFLAGS) $$(filter %.a %.o,$$^) $$(LDLIBS) $$(LLVM_LDLIBS) $$(LDFLAGS) $$(LLVM_LDFLAGS) -o $$@
> +	$(Q)$$(CC) $$(CFLAGS) $$(filter %.a %.o,$(if $(PERMISSIVE),$$(wildcard $(TRUNNER_TEST_OBJS)),$(TRUNNER_TEST_OBJS)) $$^) $$(LDLIBS) $$(LLVM_LDLIBS) $$(LDFLAGS) $$(LLVM_LDFLAGS) -o $$@

Does this duplicate every test object on the linker command line in
the default (non-PERMISSIVE) build?

When PERMISSIVE is not set, the $(if) on the prerequisite line
resolves to $(TRUNNER_TEST_OBJS), keeping them as normal
prerequisites. That means $^ already contains all test objects.

The $(if) in the recipe also resolves to $(TRUNNER_TEST_OBJS),
which is prepended before $$^. After expansion, the $(filter)
input becomes:

  $(TRUNNER_TEST_OBJS) $^
  ^^^^^^^^^^^^^^^^^^^^^
  already present in $^ as normal prerequisites

$(filter) does not deduplicate, so every .test.o file appears
twice in the linker arguments. With the default BPF_STRICT_BUILD=1
this would cause "multiple definition" errors from the linker for
all test entry points (test_arena_atomics, test_ringbuf, etc.).

The PERMISSIVE path looks correct because test objects are
order-only there and are excluded from $^, so the
$(wildcard ...) expansion is the only source.

One possible fix would be to omit the explicit
$(TRUNNER_TEST_OBJS) from the filter text in the non-PERMISSIVE
case, since $^ already carries them in the right order:

  $(filter %.a %.o,$(if $(PERMISSIVE),$(wildcard $(TRUNNER_TEST_OBJS))) $^)


---
AI reviewed your patch. Please fix the bug or email reply why it's not a bug.
See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md

CI run summary: https://github.com/kernel-patches/bpf/actions/runs/24510378997

Re: [PATCH bpf-next v6 08/11] selftests/bpf: Allow test_progs to link with a partial object set

[sashiko-bot]

Sashiko AI review found 2 potential issue(s):
- [Medium] In permissive mode, moving test objects to order-only prerequisites breaks incremental builds.
- [Low] In the default non-permissive mode, the linker command duplicates all test object files, causing 'multiple definition' linker errors.
--

commit 9ee39343705c1b6b0ebaf3f229944fadafcd695b
Author: Ricardo B. Marlière <rbm@suse.com>

selftests/bpf: Allow test_progs to link with a partial object set

This commit modifies the Makefile to support a PERMISSIVE mode, shifting
TRUNNER_TEST_OBJS to an order-only prerequisite when enabled. It also alters
the linker command to filter built objects.

> diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
> index 5ad50d3ff2f8c..79991dc98ddda 100644
> --- a/tools/testing/selftests/bpf/Makefile
> +++ b/tools/testing/selftests/bpf/Makefile
[ ... ]
> @@ -758,14 +758,15 @@ endif
>  # some X.test.o files have runtime dependencies on Y.bpf.o files
>  $(OUTPUT)/$(TRUNNER_BINARY): | $(TRUNNER_BPF_OBJS)
>  
> -$(OUTPUT)/$(TRUNNER_BINARY): $(TRUNNER_TEST_OBJS)			\
> +$(OUTPUT)/$(TRUNNER_BINARY): $(if $(PERMISSIVE),,$(TRUNNER_TEST_OBJS))	\
>  			     $(TRUNNER_EXTRA_OBJS) $$(BPFOBJ)		\
>  			     $(TRUNNER_LIB_OBJS)			\
>  			     $(TRUNNER_BPFTOOL)				\
>  			     $(OUTPUT)/veristat				\
> -			     | $(TRUNNER_BINARY)-extras
> +			     | $(TRUNNER_BINARY)-extras			\
> +			     $(if $(PERMISSIVE),$(TRUNNER_TEST_OBJS))

When PERMISSIVE is set, $(TRUNNER_TEST_OBJS) are moved exclusively to the
order-only prerequisites list.

Since order-only prerequisites do not trigger a rebuild if they are newer than
the target, could this regression break incremental builds? If a test C file
is modified, the .test.o object file will be properly recompiled, but it
appears the test binary will not be relinked because none of its normal
prerequisites have changed.

>  	$$(call msg,BINARY,,$$@)
> -	$(Q)$$(CC) $$(CFLAGS) $$(filter %.a %.o,$$^) $$(LDLIBS) $$(LLVM_LDLIBS) $$(LDFLAGS) $$(LLVM_LDFLAGS) -o $$@
> +	$(Q)$$(CC) $$(CFLAGS) $$(filter %.a %.o,$(if $(PERMISSIVE),$$(wildcard $(TRUNNER_TEST_OBJS)),$(TRUNNER_TEST_OBJS)) $$^) $$(LDLIBS) $$(LLVM_LDLIBS) $$(LDFLAGS) $$(LLVM_LDFLAGS) -o $$@

When PERMISSIVE is empty (the default behavior), $(TRUNNER_TEST_OBJS) is added
as a normal prerequisite, appearing at the beginning of the $$^ variable.

The modified recipe prepends $(TRUNNER_TEST_OBJS) to $$^ in the filter
command, making the expression evaluate to:

$$(filter %.a %.o, $(TRUNNER_TEST_OBJS) $$^)

Because Make's filter function retains all matched words and does not
deduplicate them, will this regression pass every .test.o file twice to the
linker and cause multiple definition errors?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260416-selftests-bpf_misconfig-v6-0-7efeab504af1@suse.com?part=8