selftests/bpf: Pass through build flags to bpftool and resolve_btfids

EXTRA_* and SAN_* build flags were not correctly propagated to bpftool
and resolve_btids when building selftests/bpf. This led to various
build errors on attempt to build with SAN_CFLAGS="-fsanitize=address",
for example.

Fix the makefiles to address this:
  - Pass SAN_CFLAGS/SAN_LDFLAGS to bpftool and resolve_btfids build
  - Propagate EXTRA_LDFLAGS to resolve_btfids link command
  - Use pkg-config to detect zlib and zstd for resolve_btfids, similar
    libelf handling

Also check for ASAN flag in selftests/bpf/Makefile for convenience.

Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Link: https://lore.kernel.org/r/20260223190736.649171-7-ihor.solodrai@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

diff --git a/tools/bpf/resolve_btfids/Makefile b/tools/bpf/resolve_btfids/Makefile
index 1733a6e93a07655f8ef9655897630b1a4c7bf5fe..ef083602b73a200fc0e5f71003a3313b873bf5e1 100644 (file)
--- a/tools/bpf/resolve_btfids/Makefile
+++ b/tools/bpf/resolve_btfids/Makefile
@@ -65,6 +65,9 @@ $(BPFOBJ): $(wildcard $(LIBBPF_SRC)/*.[ch] $(LIBBPF_SRC)/Makefile) | $(LIBBPF_OU
 LIBELF_FLAGS := $(shell $(HOSTPKG_CONFIG) libelf --cflags 2>/dev/null)
 LIBELF_LIBS  := $(shell $(HOSTPKG_CONFIG) libelf --libs 2>/dev/null || echo -lelf)
 
+ZLIB_LIBS  := $(shell $(HOSTPKG_CONFIG) zlib --libs 2>/dev/null || echo -lz)
+ZSTD_LIBS  := $(shell $(HOSTPKG_CONFIG) libzstd --libs 2>/dev/null || echo -lzstd)
+
 HOSTCFLAGS_resolve_btfids += -g \
           -I$(srctree)/tools/include \
           -I$(srctree)/tools/include/uapi \
@@ -73,7 +76,7 @@ HOSTCFLAGS_resolve_btfids += -g \
           $(LIBELF_FLAGS) \
           -Wall -Werror
 
-LIBS = $(LIBELF_LIBS) -lz
+LIBS = $(LIBELF_LIBS) $(ZLIB_LIBS) $(ZSTD_LIBS)
 
 export srctree OUTPUT HOSTCFLAGS_resolve_btfids Q HOSTCC HOSTLD HOSTAR
 include $(srctree)/tools/build/Makefile.include
@@ -83,7 +86,7 @@ $(BINARY_IN): fixdep FORCE prepare | $(OUTPUT)
 
 $(BINARY): $(BPFOBJ) $(SUBCMDOBJ) $(BINARY_IN)
        $(call msg,LINK,$@)
-       $(Q)$(HOSTCC) $(BINARY_IN) $(KBUILD_HOSTLDFLAGS) -o $@ $(BPFOBJ) $(SUBCMDOBJ) $(LIBS)
+       $(Q)$(HOSTCC) $(BINARY_IN) $(KBUILD_HOSTLDFLAGS) $(EXTRA_LDFLAGS) -o $@ $(BPFOBJ) $(SUBCMDOBJ) $(LIBS)
 
 clean_objects := $(wildcard $(OUTPUT)/*.o                \
                             $(OUTPUT)/.*.o.cmd           \

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 6776158f1f3e62531dc2d95f17c9080177a7155b..72a9ba41f95ebb825d25799c07ba3f0311243e45 100644 (file)
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -27,7 +27,11 @@ ifneq ($(wildcard $(GENHDR)),)
 endif
 
 BPF_GCC                ?= $(shell command -v bpf-gcc;)
+ifdef ASAN
+SAN_CFLAGS     ?= -fsanitize=address -fno-omit-frame-pointer
+else
 SAN_CFLAGS     ?=
+endif
 SAN_LDFLAGS    ?= $(SAN_CFLAGS)
 RELEASE                ?=
 OPT_FLAGS      ?= $(if $(RELEASE),-O2,-O0)
@@ -326,8 +330,8 @@ $(DEFAULT_BPFTOOL): $(wildcard $(BPFTOOLDIR)/*.[ch] $(BPFTOOLDIR)/Makefile)    \
                    $(HOST_BPFOBJ) | $(HOST_BUILD_DIR)/bpftool
        $(Q)$(MAKE) $(submake_extras)  -C $(BPFTOOLDIR)                        \
                    ARCH= CROSS_COMPILE= CC="$(HOSTCC)" LD="$(HOSTLD)"         \
-                   EXTRA_CFLAGS='-g $(OPT_FLAGS) $(EXTRA_CFLAGS)'             \
-                   EXTRA_LDFLAGS='$(EXTRA_LDFLAGS)'                           \
+                   EXTRA_CFLAGS='-g $(OPT_FLAGS) $(SAN_CFLAGS) $(EXTRA_CFLAGS)'               \
+                   EXTRA_LDFLAGS='$(SAN_LDFLAGS) $(EXTRA_LDFLAGS)'                            \
                    OUTPUT=$(HOST_BUILD_DIR)/bpftool/                          \
                    LIBBPF_OUTPUT=$(HOST_BUILD_DIR)/libbpf/                    \
                    LIBBPF_DESTDIR=$(HOST_SCRATCH_DIR)/                        \
@@ -338,8 +342,8 @@ $(CROSS_BPFTOOL): $(wildcard $(BPFTOOLDIR)/*.[ch] $(BPFTOOLDIR)/Makefile)   \
                    $(BPFOBJ) | $(BUILD_DIR)/bpftool
        $(Q)$(MAKE) $(submake_extras)  -C $(BPFTOOLDIR)                         \
                    ARCH=$(ARCH) CROSS_COMPILE=$(CROSS_COMPILE)                 \
-                   EXTRA_CFLAGS='-g $(OPT_FLAGS) $(EXTRA_CFLAGS)'              \
-                   EXTRA_LDFLAGS='$(EXTRA_LDFLAGS)'                            \
+                   EXTRA_CFLAGS='-g $(OPT_FLAGS) $(SAN_CFLAGS) $(EXTRA_CFLAGS)'               \
+                   EXTRA_LDFLAGS='$(SAN_LDFLAGS) $(EXTRA_LDFLAGS)'                            \
                    OUTPUT=$(BUILD_DIR)/bpftool/                                \
                    LIBBPF_OUTPUT=$(BUILD_DIR)/libbpf/                          \
                    LIBBPF_DESTDIR=$(SCRATCH_DIR)/                              \
@@ -404,6 +408,7 @@ $(RESOLVE_BTFIDS): $(HOST_BPFOBJ) | $(HOST_BUILD_DIR)/resolve_btfids        \
        $(Q)$(MAKE) $(submake_extras) -C $(TOOLSDIR)/bpf/resolve_btfids \
                CC="$(HOSTCC)" LD="$(HOSTLD)" AR="$(HOSTAR)" \
                LIBBPF_INCLUDE=$(HOST_INCLUDE_DIR) \
+               EXTRA_LDFLAGS='$(SAN_LDFLAGS) $(EXTRA_LDFLAGS)' \
                OUTPUT=$(HOST_BUILD_DIR)/resolve_btfids/ BPFOBJ=$(HOST_BPFOBJ)
 
 # Get Clang's default includes on this system, as opposed to those seen by