[PATCH bpf-next v8 00/11] selftests/bpf: Tolerate partial builds across kernel configs

[PATCH bpf-next v8 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 585 subtests, against the total of
717. 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

---
Changes in v8:
- In permissive mode, keep source changes to already-built tests
  triggering relinks, while using recipe-time $(wildcard ...) to pick
  up fresh .test.o files without duplicate linker inputs (patch 8)
- Resolve relative O=/KBUILD_OUTPUT before recursing into test_kmods,
  and only treat it as a kernel build dir when it contains
  Module.symvers (patch 2)
- Note in the commit message that PERMISSIVE-mode bisecting here needs
  the next two patches (patch 6)
- Clarify in the commit message that order-only skeleton prereqs do not
  break the new-skel-via-local-header case (patch 5)
- Exclude not-built tests from the success count so summary and JSON
  report them only as skipped (patch 7)
- Tighten commit messages for accuracy and clarity
- Link to v7: https://patch.msgid.link/20260416-selftests-bpf_misconfig-v7-0-a078e18012e4@suse.com

Changes in v7:
- Use $(abspath) for KMOD_O so relative O= paths resolve correctly
  when make -C changes directory (patch 2)
- Guard make clean against missing KDIR unconditionally; there is
  nothing to clean when kernel headers are absent (patch 2)
- Drop explicit $(TRUNNER_TEST_OBJS) from linker filter in strict mode;
  $^ already contains them as normal prerequisites (patch 8)
- Link to v6: https://patch.msgid.link/20260416-selftests-bpf_misconfig-v6-0-7efeab504af1@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)
- Use $(abspath) for KMOD_O so relative O= paths resolve correctly
  when make -C changes directory (patch 2)
- Guard make clean against missing KDIR unconditionally so cleaning
  does not abort when kernel headers 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)
- Drop explicit $(TRUNNER_TEST_OBJS) from linker filter in strict mode;
  they are already in $^ as normal prerequisites (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
Assisted-by: {codex,claude}
Tested-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Ricardo B. Marliere <rbm@suse.com>

---
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               | 171 ++++++++++++++-------
 .../testing/selftests/bpf/prog_tests/bpf_cookie.c  |  17 +-
 tools/testing/selftests/bpf/prog_tests/iters.c     |   2 -
 tools/testing/selftests/bpf/prog_tests/test_lsm.c  |  22 ---
 tools/testing/selftests/bpf/test_kmods/Makefile    |  30 +++-
 tools/testing/selftests/bpf/test_progs.c           |  53 ++++++-
 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, 219 insertions(+), 95 deletions(-)
---
base-commit: 9f5b3ffc3f1dac7204e32eeeff84bc5cc55c393e
change-id: 20260401-selftests-bpf_misconfig-4c33ef5c56da

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

[PATCH bpf-next v8 01/11] selftests/bpf: Add BPF_STRICT_BUILD toggle

[Ricardo B. Marlière]

Distro kernels often lack BTF types or kernel features required by some BPF
selftests, causing the build to abort on the first failure and preventing
the remaining tests from running.

Add BPF_STRICT_BUILD (default 1) to control build failure tolerance. When
set to 0, the PERMISSIVE make variable is assigned a non-empty value that
subsequent Makefile rules use to make individual build steps non-fatal.
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 97ee61f2ade5..6094fe99b5f6 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)))

-- 
2.54.0

[PATCH bpf-next v8 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, there was no fallback and the build would fail
unconditionally.

When O= or KBUILD_OUTPUT points at a prepared kernel build directory (one
containing Module.symvers), pass it through so kbuild can locate the
correct build infrastructure. Note that module artifacts still land in the
M= directory (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) is
intentionally not treated as a kernel build directory to avoid passing an
unrelated directory to kbuild. The parent bpf/Makefile resolves O= and
KBUILD_OUTPUT to absolute paths before invoking the test_kmods sub-make so
relative paths anchor to the user's invocation directory rather than the
sub-make's CWD.

Guard the clean target against a missing KDIR unconditionally. In
permissive mode, also guard the all target and make the parent Makefile's
cp step conditional so that a missing or unbuilt module does not abort the
build.

Signed-off-by: Ricardo B. Marlière <rbm@suse.com>
---
 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..dcba595b4b99 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=) \
+		M=$(TEST_KMOD_DIR) modules
+else ifneq ("$(wildcard $(KDIR))", "")
+	$(Q)$(MAKE) -C $(KDIR) $(if $(KMOD_O_VALID),O=$(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=) \
+		M=$(TEST_KMOD_DIR) clean
+endif

-- 
2.54.0

[PATCH bpf-next v8 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 in permissive mode:
emit SKIP-BPF or SKIP-SKEL to stderr, 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 abort the build when any dependency is missing.

Note that progress messages (GEN-SKEL, LINK-BPF) are also redirected to
stderr as a side effect of rewriting the recipes into single-shell
pipelines; the $(call msg,...) macro is a make-recipe construct that cannot
be used inside an &&-chained shell command sequence.

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 cc6ee7a2df93..b104c687dcf0 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -485,22 +485,26 @@ $(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
@@ -607,47 +611,81 @@ $(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

-- 
2.54.0

[PATCH bpf-next v8 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 b104c687dcf0..9a4d8bea0c18 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -170,7 +170,7 @@ 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
@@ -732,7 +732,7 @@ $(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
 

-- 
2.54.0

[PATCH bpf-next v8 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.

Make skeletons and BPFOBJ order-only prerequisites of .test.d so that a
missing or skipped skeleton does not prevent .test.d generation, and
regenerating a skeleton or rebuilding libbpf.a 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.

Note that adding a new BPF skeleton via a modified existing local header
still works correctly: GNU make builds order-only prerequisites that do not
exist (the order-only qualifier only suppresses timestamp-driven rebuilds,
not existence-driven builds), so a brand-new .skel.h listed in
TRUNNER_BPF_SKELS is generated even when .test.d is otherwise up to date.
The modified local header invalidates .test.o through the previously
included .d content, forcing a recompile that regenerates .test.d with the
new .skel.h dependency captured by gcc -MMD.

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 9a4d8bea0c18..608e6dff0392 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -726,11 +726,11 @@ $(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))

-- 
2.54.0

[PATCH bpf-next v8 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 in permissive mode: 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.

Note on bisectability: this change is gated entirely behind PERMISSIVE, so
default builds (BPF_STRICT_BUILD!=0) compile and run identically at every
commit. In PERMISSIVE mode, this commit alone is incomplete: the linker
still rejects missing objects and the runtime still aborts on NULL function
pointers; those issues are addressed by the two commits that follow in this
series.

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 608e6dff0392..f0545ee6b32a 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -717,11 +717,14 @@ $(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			\

-- 
2.54.0

[PATCH bpf-next v8 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 | 53 +++++++++++++++++++++++++++-----
 tools/testing/selftests/bpf/test_progs.h |  1 +
 2 files changed, 46 insertions(+), 8 deletions(-)

diff --git a/tools/testing/selftests/bpf/test_progs.c b/tools/testing/selftests/bpf/test_progs.c
index cc14b13e23fe..7ba82974ee78 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)
@@ -1641,6 +1645,7 @@ static void calculate_summary_and_print_errors(struct test_env *env)
 	json_writer_t *w = NULL;
 
 	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 (!state->tested)
@@ -1651,7 +1656,7 @@ static void calculate_summary_and_print_errors(struct test_env *env)
 
 		if (state->error_cnt)
 			fail_cnt++;
-		else
+		else if (!test->not_built)
 			succ_cnt++;
 	}
 
@@ -1700,8 +1705,13 @@ 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 +1782,19 @@ 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 +2069,20 @@ 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 +2134,18 @@ 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 37955a8ad385..2cf950afcd85 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 */

-- 
2.54.0

[PATCH bpf-next v8 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.

In permissive mode, declare the test objects that already exist on disk
(via parse-time $(wildcard ...)) as normal prerequisites of the binary so
that modifications to a test source still trigger a relink, and keep the
full TRUNNER_TEST_OBJS list as order-only prerequisites so that initial
fresh builds still produce them and missing objects do not abort the link.
The recipe filter is split per mode: in permissive mode it combines a
recipe-time $(wildcard ...) (which catches objects freshly produced via the
order-only path on a fresh build) with $(filter-out
$(TRUNNER_TEST_OBJS),$^) (which keeps the non-test inputs from $^ but drops
the parse-time wildcard duplicates). This avoids passing the same .test.o
twice to the linker while still presenting test objects before libbpf.a so
that GNU ld, which scans static archives left-to-right, pulls in archive
members referenced exclusively by test objects (e.g. ring_buffer__new from
ringbuf.c). In default (strict) mode the recipe remains the simple $(filter
%.a %.o,$^) since TRUNNER_TEST_OBJS is part of $^ exactly once.

Note: adding a brand-new test_*.c file in permissive mode requires removing
the binary (or a clean rebuild) before the new test is linked in, because
the parse-time $(wildcard ...) is evaluated when the Makefile is read and
will not yet see the new .test.o. This is acceptable since permissive mode
targets tolerant CI builds rather than incremental development.

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 f0545ee6b32a..9a5177455f0a 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -767,14 +767,15 @@ 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),$$(wildcard $(TRUNNER_TEST_OBJS)),$(TRUNNER_TEST_OBJS))	\
 			     $(TRUNNER_EXTRA_OBJS) $$(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) $$(CFLAGS) $(if $(PERMISSIVE),$$(filter %.a %.o,$$(wildcard $(TRUNNER_TEST_OBJS)) $$(filter-out $(TRUNNER_TEST_OBJS),$$^)),$$(filter %.a %.o,$$^)) $$(LDLIBS) $$(LLVM_LDLIBS) $$(LDFLAGS) $$(LLVM_LDFLAGS) -o $$@
 	$(Q)ln -sf $(if $2,..,.)/tools/build/bpftool/$(USE_BOOTSTRAP)bpftool \
 		   $(OUTPUT)/$(if $2,$2/)bpftool
 

-- 
2.54.0

[PATCH bpf-next v8 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 9a5177455f0a..461e2d9416fc 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -939,7 +939,8 @@ $(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 \
@@ -982,7 +983,8 @@ $(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:
 #

-- 
2.54.0

[PATCH bpf-next v8 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     |  2 --
 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, 29 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..c0b6082f345a 100644
--- a/tools/testing/selftests/bpf/prog_tests/iters.c
+++ b/tools/testing/selftests/bpf/prog_tests/iters.c
@@ -202,8 +202,6 @@ 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 */

-- 
2.54.0

[PATCH bpf-next v8 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 461e2d9416fc..3c3234a2ce15 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -1017,12 +1017,23 @@ 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
 

-- 
2.54.0