diff options
| author |   Yonghong Song <yhs@fb.com> | 2022-02-04 13:43:55 -0800 |
|---|---|---|
| committer |   Andrii Nakryiko <andrii@kernel.org> | 2022-02-04 18:22:56 -0800 |
| commit | 0908a66ad1124c1634c33847ac662106f7f2c198 (patch) | |
| tree | b27165af017bf180da8da1f966758533a3d67ad1 | |
| parent | selftests/bpf: Test bpf_core_types_are_compat() functionality. (diff) | |
| download | linux-dev-0908a66ad1124c1634c33847ac662106f7f2c198.tar.xz linux-dev-0908a66ad1124c1634c33847ac662106f7f2c198.zip | |
libbpf: Fix build issue with llvm-readelf
There are cases where clang compiler is packaged in a way
readelf is a symbolic link to llvm-readelf. In such cases,
llvm-readelf will be used instead of default binutils readelf,
and the following error will appear during libbpf build:
Warning: Num of global symbols in
/home/yhs/work/bpf-next/tools/testing/selftests/bpf/tools/build/libbpf/sharedobjs/libbpf-in.o (367)
does NOT match with num of versioned symbols in
/home/yhs/work/bpf-next/tools/testing/selftests/bpf/tools/build/libbpf/libbpf.so libbpf.map (383).
Please make sure all LIBBPF_API symbols are versioned in libbpf.map.
--- /home/yhs/work/bpf-next/tools/testing/selftests/bpf/tools/build/libbpf/libbpf_global_syms.tmp ...
+++ /home/yhs/work/bpf-next/tools/testing/selftests/bpf/tools/build/libbpf/libbpf_versioned_syms.tmp ...
@@ -324,6 +324,22 @@
btf__str_by_offset
btf__type_by_id
btf__type_cnt
+LIBBPF_0.0.1
+LIBBPF_0.0.2
+LIBBPF_0.0.3
+LIBBPF_0.0.4
+LIBBPF_0.0.5
+LIBBPF_0.0.6
+LIBBPF_0.0.7
+LIBBPF_0.0.8
+LIBBPF_0.0.9
+LIBBPF_0.1.0
+LIBBPF_0.2.0
+LIBBPF_0.3.0
+LIBBPF_0.4.0
+LIBBPF_0.5.0
+LIBBPF_0.6.0
+LIBBPF_0.7.0
libbpf_attach_type_by_name
libbpf_find_kernel_btf
libbpf_find_vmlinux_btf_id
make[2]: *** [Makefile:184: check_abi] Error 1
make[1]: *** [Makefile:140: all] Error 2
The above failure is due to different printouts for some ABS
versioned symbols. For example, with the same libbpf.so,
$ /bin/readelf --dyn-syms --wide tools/lib/bpf/libbpf.so | grep "LIBBPF" | grep ABS
134: 0000000000000000 0 OBJECT GLOBAL DEFAULT ABS LIBBPF_0.5.0
202: 0000000000000000 0 OBJECT GLOBAL DEFAULT ABS LIBBPF_0.6.0
...
$ /opt/llvm/bin/readelf --dyn-syms --wide tools/lib/bpf/libbpf.so | grep "LIBBPF" | grep ABS
134: 0000000000000000 0 OBJECT GLOBAL DEFAULT ABS LIBBPF_0.5.0@@LIBBPF_0.5.0
202: 0000000000000000 0 OBJECT GLOBAL DEFAULT ABS LIBBPF_0.6.0@@LIBBPF_0.6.0
...
The binutils readelf doesn't print out the symbol LIBBPF_* version and llvm-readelf does.
Such a difference caused libbpf build failure with llvm-readelf.
The proposed fix filters out all ABS symbols as they are not part of the comparison.
This works for both binutils readelf and llvm-readelf.
Reported-by: Delyan Kratunov <delyank@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20220204214355.502108-1-yhs@fb.com
| -rw-r--r-- | tools/lib/bpf/Makefile | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/tools/lib/bpf/Makefile b/tools/lib/bpf/Makefile index f947b61b2107..b8b37fe76006 100644 --- a/tools/lib/bpf/Makefile +++ b/tools/lib/bpf/Makefile @@ -131,7 +131,7 @@ GLOBAL_SYM_COUNT = $(shell readelf -s --wide $(BPF_IN_SHARED) | \ sort -u | wc -l) VERSIONED_SYM_COUNT = $(shell readelf --dyn-syms --wide $(OUTPUT)libbpf.so | \ sed 's/\[.*\]//' | \ - awk '/GLOBAL/ && /DEFAULT/ && !/UND/ {print $$NF}' | \ + awk '/GLOBAL/ && /DEFAULT/ && !/UND|ABS/ {print $$NF}' | \ grep -Eo '[^ ]+@LIBBPF_' | cut -d@ -f1 | sort -u | wc -l) CMD_TARGETS = $(LIB_TARGET) $(PC_FILE) @@ -194,7 +194,7 @@ check_abi: $(OUTPUT)libbpf.so $(VERSION_SCRIPT) sort -u > $(OUTPUT)libbpf_global_syms.tmp; \ readelf --dyn-syms --wide $(OUTPUT)libbpf.so | \ sed 's/\[.*\]//' | \ - awk '/GLOBAL/ && /DEFAULT/ && !/UND/ {print $$NF}'| \ + awk '/GLOBAL/ && /DEFAULT/ && !/UND|ABS/ {print $$NF}'| \ grep -Eo '[^ ]+@LIBBPF_' | cut -d@ -f1 | \ sort -u > $(OUTPUT)libbpf_versioned_syms.tmp; \ diff -u $(OUTPUT)libbpf_global_syms.tmp \ |