[PATCH bpf-next v5 03/11] selftests/bpf: Tolerate BPF and skeleton generation failures

Ricardo B. Marlière
2026-04-15T20:59:42Z

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 | 104 +++++++++++++++++++++++------------
1 file changed, 69 insertions(+), 35 deletions(-)

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 5c4cdf1dafc8..a305d13409e4 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 +602,77 @@ $(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 $$< ]; then \
+ printf ' %-12s %s\n' 'SKIP-SKEL' '$$(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 \
+ 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 \
+ 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 $$$$f ]; then \
+ printf ' %-12s %s\n' 'SKIP-SKEL' '$$(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