On 4/11/21 10:31 AM, Sedat Dilek wrote:
On Sun, Apr 11, 2021 at 7:20 PM Yonghong Song <yhs@xxxxxx> wrote:
On 4/11/21 3:47 AM, Sedat Dilek wrote:
On Sat, Apr 10, 2021 at 6:49 PM Yonghong Song <yhs@xxxxxx> wrote:
With clang compiler:
make -j60 LLVM=1 LLVM_IAS=1 <=== compile kernel
make -j60 -C tools/testing/selftests/bpf LLVM=1 LLVM_IAS=1
the test_cpp build failed due to the failure:
warning: treating 'c-header' input as 'c++-header' when in C++ mode, this behavior is deprecated [-Wdeprecated]
clang-13: warning: cannot specify -o when generating multiple output files
test_cpp compilation flag looks like:
clang++ -g -Og -rdynamic -Wall -I<...> ... \
-Dbpf_prog_load=bpf_prog_test_load -Dbpf_load_program=bpf_test_load_program \
test_cpp.cpp <...>/test_core_extern.skel.h <...>/libbpf.a <...>/test_stub.o \
-lcap -lelf -lz -lrt -lpthread -o <...>/test_cpp
The clang++ compiler complains the header file in the command line.
Let us remove the header file from the command line which is not intended
any way, and this fixed the problem.
Signed-off-by: Yonghong Song <yhs@xxxxxx>
---
tools/testing/selftests/bpf/Makefile | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 6448c626498f..bbd61cc3889b 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -481,7 +481,7 @@ $(OUTPUT)/test_verifier: test_verifier.c verifier/tests.h $(BPFOBJ) | $(OUTPUT)
# Make sure we are able to include and link libbpf against c++.
$(OUTPUT)/test_cpp: test_cpp.cpp $(OUTPUT)/test_core_extern.skel.h $(BPFOBJ)
$(call msg,CXX,,$@)
- $(Q)$(CXX) $(CFLAGS) $^ $(LDLIBS) -o $@
+ $(Q)$(CXX) $(CFLAGS) test_cpp.cpp $(BPFOBJ) $(LDLIBS) -o $@
# Benchmark runner
$(OUTPUT)/bench_%.o: benchs/bench_%.c bench.h
--
2.30.2
NOTE: bpf-next might be different from my build-environment.
Yonghong, can you please re-test by adding explicitly CXX=g++ to your make line?
Here I have:
$ grep test_cpp make-log_tools-testing-selftests-bpf_clang_clang++.txt
1907:clang++ -g -rdynamic -Wall -O2 -DHAVE_GENHDR
-I/home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf
-I/home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf/tools/include
-I/home/dileks/src/linux-kernel/git/include/generated
-I/home/dileks/src/linux-kernel/git/tools/lib
-I/home/dileks/src/linux-kernel/git/tools/include
-I/home/dileks/src/linux-kernel/git/tools/include/uapi
-I/home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf
-Wno-unused-command-line-argument -Wno-format-security
-Dbpf_prog_load=bpf_prog_test_load
-Dbpf_load_program=bpf_test_load_program test_cpp.cpp
/home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf/tools/build/libbpf/libbpf.a
-lcap -lelf -lz -lrt -lpthread -o
/home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf/test_cpp
This clang++ line does not include <...>/test_core_extern.skel.h ^^^
$ grep test_core_extern.skel.h
make-log_tools-testing-selftests-bpf_clang_clang++.txt
704:/home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf/tools/sbin/bpftool
gen skeleton /home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf/test_co
re_extern.o > /home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf/test_core_extern.skel.h
1592:/home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf/tools/sbin/bpftool
gen skeleton /home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf/no_alu
32/test_core_extern.o >
/home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf/no_alu32/test_core_extern.skel.h
Checking test_cpp:
$ /opt/llvm-toolchain/bin/llvm-objdump-12 -Dr test_cpp | grep extern
0000000000417e50 <cmp_externs>:
417e54: 75 22 jne 0x417e78 <cmp_externs+0x28>
417e59: 75 10 jne 0x417e6b <cmp_externs+0x1b>
417e61: 75 21 jne 0x417e84 <cmp_externs+0x34>
417e69: 75 1e jne 0x417e89 <cmp_externs+0x39>
417e87: eb f2 jmp 0x417e7b <cmp_externs+0x2b>
417e8c: eb ed jmp 0x417e7b <cmp_externs+0x2b>
$ /opt/llvm-toolchain/bin/llvm-objdump-12 -Dr test_cpp | grep core_extern
[ EMPTY ]
When compiled with g++ in an earlier setup this contained "core_extern".
With this version of your patchser it breaks *here* when using CXX=g++
(and uses /usr/bin/ld as linker):
g++ -g -rdynamic -Wall -O2 -DHAVE_GENHDR
-I/home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf
-I/home/dileks/src/linux-kernel/git/tools/testing/selftests/b
pf/tools/include -I/home/dileks/src/linux-kernel/git/include/generated
-I/home/dileks/src/linux-kernel/git/tools/lib
-I/home/dileks/src/linux-kernel/git/tools/include
-I/home/dileks/src/linux-kernel/git/tools/include/uapi
-I/home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf
-Wno-unused-command-line-argument -Wno-format-security
-Dbpf_prog_load=bpf_prog_test_load
-Dbpf_load_program=bpf_test_load_program test_cpp.cpp
/home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf/tools/build/libbpf/libbpf.a
-lcap -lelf -lz -lrt -lpthread -o
/home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf/test_cpp
/usr/bin/ld: /home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf/tools/build/libbpf/libbpf.a(libbpf-in.o):
relocation R_X86_64_32 against `.rodata.str1.1' ca
n not be used when making a PIE object; recompile with -fPIE
collect2: error: ld returned 1 exit status
make: *** [Makefile:457:
/home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf/test_cpp]
Error 1
I cannot reproduce the issue with g++ with bpf-next, my command line is
g++ -g -Og -rdynamic -Wall
-I/home/yhs/work/bpf-next/tools/testing/selftests/bpf
-I/home/yhs/work/bpf-next/tools/testing/selftests/bpf/tools/include
-I/home/yhs/work/bpf-next/include/generated
-I/home/yhs/work/bpf-next/tools/lib
-I/home/yhs/work/bpf-next/tools/include
-I/home/yhs/work/bpf-next/tools/include/uapi
-I/home/yhs/work/bpf-next/tools/testing/selftests/bpf
-Wno-unused-command-line-argument -Wno-format-security
-Dbpf_prog_load=bpf_prog_test_load
-Dbpf_load_program=bpf_test_load_program test_cpp.cpp
/home/yhs/work/bpf-next/tools/testing/selftests/bpf/tools/build/libbpf/libbpf.a
-lcap -lelf -lz -lrt -lpthread -o
/home/yhs/work/bpf-next/tools/testing/selftests/bpf/test_cpp
I modified to
g++ -g -rdynamic -Wall -O2 -DHAVE_GENHDR
-I/home/yhs/work/bpf-next/tools/testing/selftests/bpf ...
and cannot reproduce the issue.
The macro HAVE_GENHDR is only effect for test_verifier.
Could you try to run the above g++ command by adding
test_core_extern.skel.h back, something like
> g++ -g -rdynamic -Wall -O2 -DHAVE_GENHDR
> -I/home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf
> -I/home/dileks/src/linux-kernel/git/tools/testing/selftests/b
> pf/tools/include -I/home/dileks/src/linux-kernel/git/include/generated
> -I/home/dileks/src/linux-kernel/git/tools/lib
> -I/home/dileks/src/linux-kernel/git/tools/include
> -I/home/dileks/src/linux-kernel/git/tools/include/uapi
> -I/home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf
> -Wno-unused-command-line-argument -Wno-format-security
> -Dbpf_prog_load=bpf_prog_test_load
> -Dbpf_load_program=bpf_test_load_program test_cpp.cpp
> test_core_extern.skel.h
>
/home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf/tools/build/libbpf/libbpf.a
> -lcap -lelf -lz -lrt -lpthread -o
> /home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf/test_cpp
The issue could be somewhere else?
I have seen all that *skel* was reworked in bpf-next, so this is an issue here.
Adding test_core_extern.skel.h:
$ cd /tools/testing/selftests/bpf/
$ file test_core_extern.skel.h
test_core_extern.skel.h: C source, ASCII text
$ g++ -g -rdynamic -Wall -O2 -DHAVE_GENHDR
-I/home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf
-I/home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf/tools/include
-I/home/dileks/src/linux-kernel/git/include/generated
-I/home/dileks/src/linux-kernel/git/tools/lib
-I/home/dileks/src/linux-kernel/git/tools/include
-I/home/dileks/src/linux-kernel/git/tools/include/uapi
-I/home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf
-Wno-unused-command-line-argument -Wno-format-security
-Dbpf_prog_load=bpf_prog_test_load
-Dbpf_load_program=bpf_test_load_program test_cpp.cpp
test_core_extern.skel.h
/home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf/tools/build/libbpf/libbpf.a
-lcap -lelf -lz -lrt -lpthread -o
/home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf/test_cpp
/usr/bin/ld: /home/dileks/src/linux-kernel/git/tools/testing/selftests/bpf/tools/build/libbpf/libbpf.a(libbpf-in.o):
relocation R_X86_64_32 against `.rodata.str1.1' ca
n not be used when making a PIE object; recompile with -fPIE
collect2: error: ld returned 1 exit status
So the issue is not related to this patch since adding
test_core_extern.skel.h the failure is still there.
So looks like this is g++ compilation issue. So you should be
able to reproduce the issue without this patch set, right?
My gcc compiled libbpf.a also has a bunch of R_X86_64_32 relations
against the .rodata.str1.1 section:
$ readelf -r libbpf.a | less
File: libbpf.a(libbpf-in.o)
Relocation section '.rela.text' at offset 0x11a4b8 contains 3152 entries:
Offset Info Type Sym. Value Sym. Name
+ Addend
000000000136 00020000000b R_X86_64_32S 0000000000000000 .rodata + 0
00000000013b 00030000000a R_X86_64_32 0000000000000000
.rodata.str1.1 + 6e
000000000141 00030000000a R_X86_64_32 0000000000000000
.rodata.str1.1 + c
000000000147 00030000000a R_X86_64_32 0000000000000000
.rodata.str1.1 + 10
00000000014d 00030000000a R_X86_64_32 0000000000000000
.rodata.str1.1 + 16
000000000153 00030000000a R_X86_64_32 0000000000000000
.rodata.str1.1 + 1d
000000000159 00030000000a R_X86_64_32 0000000000000000
.rodata.str1.1 + 23
00000000015f 00030000000a R_X86_64_32 0000000000000000
.rodata.str1.1 + 28
...
and I did not see any issues.
Adding '-###' to the compilation flags you can find the flags for
each subcommand, for linker, I have
/usr/libexec/gcc/x86_64-redhat-linux/8/collect2 -plugin
/usr/libexec/gcc/x86_64-redhat-linux/8/liblto_plugin.so
"-plugin-opt=/usr/libexec/gcc/x86_64-redhat-linux/8/lto-wrapper"
"-plugin-opt=-fresolution=/tmp/ccjktcVg.res"
"-plugin-opt=-pass-through=-lgcc_s" "-plugin-opt=-pass-through=-lgcc"
"-plugin-opt=-pass-through=-lc" "-plugin-opt=-pass-through=-lgcc_s"
"-plugin-opt=-pass-through=-lgcc" --build-id --no-add-needed
--eh-frame-hdr "--hash-style=gnu" -m elf_x86_64 -export-dynamic
-dynamic-linker /lib64/ld-linux-x86-64.so.2 -o
/home/yhs/work/bpf-next/tools/testing/selftests/bpf/test_cpp
/usr/lib/gcc/x86_64-redhat-linux/8/../../../../lib64/crt1.o
/usr/lib/gcc/x86_64-redhat-linux/8/../../../../lib64/crti.o
/usr/lib/gcc/x86_64-redhat-linux/8/crtbegin.o
-L/usr/lib/gcc/x86_64-redhat-linux/8
-L/usr/lib/gcc/x86_64-redhat-linux/8/../../../../lib64 -L/lib/../lib64
-L/usr/lib/../lib64 -L/usr/lib/gcc/x86_64-redhat-linux/8/../../..
/tmp/cc0xqkPi.o
/home/yhs/work/bpf-next/tools/testing/selftests/bpf/tools/build/libbpf/libbpf.a
-lcap -lelf -lz -lrt -lpthread "-lstdc++" -lm -lgcc_s -lgcc -lc -lgcc_s
-lgcc /usr/lib/gcc/x86_64-redhat-linux/8/crtend.o
/usr/lib/gcc/x86_64-redhat-linux/8/../../../../lib64/crtn.o
COLLECT_GCC_OPTIONS='-g' '-rdynamic' '-Wall' '-O2' '-D' 'HAVE_GENHDR'
'-I' '/home/yhs/work/bpf-next/tools/testing/selftests/bpf' '-I'
'/home/yhs/work/bpf-next/tools/testing/selftests/bpf/tools/include' '-I'
'/home/yhs/work/bpf-next/include/generated' '-I'
'/home/yhs/work/bpf-next/tools/lib' '-I'
'/home/yhs/work/bpf-next/tools/include' '-I'
'/home/yhs/work/bpf-next/tools/include/uapi' '-I'
'/home/yhs/work/bpf-next/tools/testing/selftests/bpf'
'-Wno-uuunused-command-line-argument' '-Wno-format-security' '-D'
'bpf_prog_load=bpf_prog_test_load' '-D'
'bpf_load_program=bpf_test_load_program' '-o'
'/home/yhs/work/bpf-next/tools/testing/selftests/bpf/test_cpp'
'-shared-libgcc' '-mtune=generic' '-march=x86-64'
Not sure whether you will see some different COLLECT_GCC_OPTIONS flags
or not.
There is not much I can do here since I cannot reproduce the issue.
Maybe you can help to narrow down the reason of the failure a little
bit more.
Write that test_cpp.cpp in C :-)?
test_cpp.cpp is intentionally to test libbpf used by a c++ application.
BTW, did you check (llvm-)objdump output?
$ /opt/llvm-toolchain/bin/llvm-objdump-12 -Dr test_cpp | grep core_extern
This is what I got with g++ compiled test_cpp:
$ llvm-objdump -Dr test_cpp | grep core_extern
406a80: e8 5b 01 00 00 callq 0x406be0
<_ZL25test_core_extern__destroyP16test_core_extern>
406ab9: e8 22 01 00 00 callq 0x406be0
<_ZL25test_core_extern__destroyP16test_core_extern>
0000000000406be0 <_ZL25test_core_extern__destroyP16test_core_extern>:
406be3: 74 1a je 0x406bff
<_ZL25test_core_extern__destroyP16test_core_extern+0x1f>
406bef: 74 05 je 0x406bf6
<_ZL25test_core_extern__destroyP16test_core_extern+0x16>
- Sedat -
$ grep test_cpp ../make-log_tools-testing-selftests-bpf_clang_g++.txt
| grep test_core_extern.skel.h
[ EMPTY ]
As said I do NOT use bpf-next.
- Sedat -
- Sedat -
