From: Quentin Monnet quentin@isovalent.com
mainline inclusion from mainline-5.16-rc1 commit bf60791741d430e8a3e2f8b4a3941d392bf838c2 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I5EUVD CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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API headers from libbpf should not be accessed directly from the library's source directory. Instead, they should be exported with "make install_headers". Let's make sure that bpf/preload/Makefile installs the headers properly when building.
Note that we declare an additional dependency for iterators/iterators.o: having $(LIBBPF_A) as a dependency to "$(obj)/bpf_preload_umd" is not sufficient, as it makes it required only at the linking step. But we need libbpf to be compiled, and in particular its headers to be exported, before we attempt to compile iterators.o. The issue would not occur before this commit, because libbpf's headers were not exported and were always available under tools/lib/bpf.
Signed-off-by: Quentin Monnet quentin@isovalent.com Signed-off-by: Andrii Nakryiko andrii@kernel.org Link: https://lore.kernel.org/bpf/20211007194438.34443-7-quentin@isovalent.com (cherry picked from commit bf60791741d430e8a3e2f8b4a3941d392bf838c2) Signed-off-by: Wang Yufen wangyufen@huawei.com --- kernel/bpf/preload/Makefile | 25 ++++++++++++++++++++----- 1 file changed, 20 insertions(+), 5 deletions(-)
diff --git a/kernel/bpf/preload/Makefile b/kernel/bpf/preload/Makefile index 1951332dd15f..469d35e890eb 100644 --- a/kernel/bpf/preload/Makefile +++ b/kernel/bpf/preload/Makefile @@ -1,21 +1,36 @@ # SPDX-License-Identifier: GPL-2.0
LIBBPF_SRCS = $(srctree)/tools/lib/bpf/ -LIBBPF_A = $(obj)/libbpf.a -LIBBPF_OUT = $(abspath $(obj)) +LIBBPF_OUT = $(abspath $(obj))/libbpf +LIBBPF_A = $(LIBBPF_OUT)/libbpf.a +LIBBPF_DESTDIR = $(LIBBPF_OUT) +LIBBPF_INCLUDE = $(LIBBPF_DESTDIR)/include
# Although not in use by libbpf's Makefile, set $(O) so that the "dummy" test # in tools/scripts/Makefile.include always succeeds when building the kernel # with $(O) pointing to a relative path, as in "make O=build bindeb-pkg". -$(LIBBPF_A): - $(Q)$(MAKE) -C $(LIBBPF_SRCS) O=$(LIBBPF_OUT)/ OUTPUT=$(LIBBPF_OUT)/ $(LIBBPF_OUT)/libbpf.a +$(LIBBPF_A): | $(LIBBPF_OUT) + $(Q)$(MAKE) -C $(LIBBPF_SRCS) O=$(LIBBPF_OUT)/ OUTPUT=$(LIBBPF_OUT)/ \ + DESTDIR=$(LIBBPF_DESTDIR) prefix= \ + $(LIBBPF_OUT)/libbpf.a install_headers + +libbpf_hdrs: $(LIBBPF_A) + +.PHONY: libbpf_hdrs + +$(LIBBPF_OUT): + $(call msg,MKDIR,$@) + $(Q)mkdir -p $@
userccflags += -I $(srctree)/tools/include/ -I $(srctree)/tools/include/uapi \ - -I $(srctree)/tools/lib/ -Wno-unused-result + -I $(LIBBPF_INCLUDE) -Wno-unused-result
userprogs := bpf_preload_umd
clean-files := $(userprogs) bpf_helper_defs.h FEATURE-DUMP.libbpf staticobjs/ feature/ +clean-files += $(LIBBPF_OUT) $(LIBBPF_DESTDIR) + +$(obj)/iterators/iterators.o: | libbpf_hdrs
bpf_preload_umd-objs := iterators/iterators.o bpf_preload_umd-userldlibs := $(LIBBPF_A) -lelf -lz