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Hi All,

I am trying to build kselftest on Linux-5.4 on ubuntu 18.04. I installed LLVM-9.0.0 and Clang-9.0.0 from below links after following steps from [1] because of discussion [2]

https://releases.llvm.org/9.0.0/llvm-9.0.0.src.tar.xz https://releases.llvm.org/9.0.0/clang-tools-extra-9.0.0.src.tar.xz https://releases.llvm.org/9.0.0/cfe-9.0.0.src.tar.xz

Now, i am trying with llc -march=bpf, with this segmentation fault is coming as below:

gcc -g -Wall -O2 -I../../../include/uapi -I../../../lib -I../../../lib/bpf -I../../../../include/generated -DHAVE_GENHDR -I../../../include -Dbpf_prog_load=bpf_prog_test_load -Dbpf_load_program=bpf_test_load_program test_flow_dissector.c /usr/src/tovards/linux/tools/testing/selftests/bpf/test_stub.o /usr/src/tovards/linux/tools/testing/selftests/bpf/libbpf.a -lcap -lelf -lrt -lpthread -o /usr/src/tovards/linux/tools/testing/selftests/bpf/test_flow_dissector gcc -g -Wall -O2 -I../../../include/uapi -I../../../lib -I../../../lib/bpf -I../../../../include/generated -DHAVE_GENHDR -I../../../include -Dbpf_prog_load=bpf_prog_test_load -Dbpf_load_program=bpf_test_load_program test_tcp_check_syncookie_user.c /usr/src/tovards/linux/tools/testing/selftests/bpf/test_stub.o /usr/src/tovards/linux/tools/testing/selftests/bpf/libbpf.a -lcap -lelf -lrt -lpthread -o /usr/src/tovards/linux/tools/testing/selftests/bpf/test_tcp_check_syncookie_user gcc -g -Wall -O2 -I../../../include/uapi -I../../../lib -I../../../lib/bpf -I../../../../include/generated -DHAVE_GENHDR -I../../../include -Dbpf_prog_load=bpf_prog_test_load -Dbpf_load_program=bpf_test_load_program test_lirc_mode2_user.c /usr/src/tovards/linux/tools/testing/selftests/bpf/test_stub.o /usr/src/tovards/linux/tools/testing/selftests/bpf/libbpf.a -lcap -lelf -lrt -lpthread -o /usr/src/tovards/linux/tools/testing/selftests/bpf/test_lirc_mode2_user (clang -I. -I./include/uapi -I../../../include/uapi -I/usr/src/tovards/linux/tools/testing/selftests/bpf/../usr/include -D__TARGET_ARCH_arm64 -g -idirafter /usr/local/include -idirafter /usr/local/lib/clang/9.0.0/include -idirafter /usr/include/aarch64-linux-gnu -idirafter /usr/include -Wno-compare-distinct-pointer-types -O2 -target bpf -emit-llvm \ -c progs/test_core_reloc_arrays.c -o - || echo "clang failed") | \ llc -march=bpf -mcpu=probe -filetype=obj -o /usr/src/tovards/linux/tools/testing/selftests/bpf/test_core_reloc_arrays.o Stack dump: 0. Program arguments: llc -march=bpf -mcpu=probe -filetype=obj -o /usr/src/tovards/linux/tools/testing/selftests/bpf/test_core_reloc_arrays.o 1. Running pass 'Function Pass Manager' on module '<stdin>'. 2. Running pass 'BPF Assembly Printer' on function '@test_core_arrays' #0 0x0000aaaac618db08 llvm::sys::PrintStackTrace(llvm::raw_ostream&) (/usr/local/bin/llc+0x152eb08) Segmentation fault Makefile:260: recipe for target '/usr/src/tovards/linux/tools/testing/selftests/bpf/test_core_reloc_arrays.o' failed make[1]: *** [/usr/src/tovards/linux/tools/testing/selftests/bpf/test_core_reloc_arrays.o] Error 139

To add more details, Commenting following lines in bpf/progs/test_core_reloc_arrays.c removes the segmentation fault.

--- a/tools/testing/selftests/bpf/progs/test_core_reloc_arrays.c +++ b/tools/testing/selftests/bpf/progs/test_core_reloc_arrays.c @@ -41,15 +41,14 @@ int test_core_arrays(void *ctx) if (BPF_CORE_READ(&out->a2, &in->a[2])) return 1; /* in->b[1][2][3] */ - if (BPF_CORE_READ(&out->b123, &in->b[1][2][3])) - return 1; +// if (BPF_CORE_READ(&out->b123, &in->b[1][2][3])) +// return 1; /* in->c[1].c */ if (BPF_CORE_READ(&out->c1c, &in->c[1].c)) return 1; /* in->d[0][0].d */ - if (BPF_CORE_READ(&out->d00d, &in->d[0][0].d)) - return 1; - +// if (BPF_CORE_READ(&out->d00d, &in->d[0][0].d)) +// return 1; return 0; }

It looks to be something related llc and more than 1 dimension array. has anyone faced such error.

Please suggest!!

--prabhakar(pk)

[1] https://stackoverflow.com/questions/47255526/how-to-build-the-latest-clang-t...

[2] https://www.mail-archive.com/netdev@vger.kernel.org/msg315096.html

Linux top-commit ---------------- commit bc88f85c6c09306bd21917e1ae28205e9cd775a7 (HEAD -> master, origin/master, origin/HEAD) Author: Ben Dooks ben.dooks@codethink.co.uk Date: Wed Oct 16 12:24:58 2019 +0100

kthread: make __kthread_queue_delayed_work static

The __kthread_queue_delayed_work is not exported so make it static, to avoid the following sparse warning:

kernel/kthread.c:869:6: warning: symbol '__kthread_queue_delayed_work' was not declared. Should it be static?

Signed-off-by: Ben Dooks ben.dooks@codethink.co.uk Signed-off-by: Linus Torvalds torvalds@linux-foundation.org