ubuntu_bpf failed to build with F-hwe-5.15

[Po-Hsu Lin]

Issue found with 5.15.0-83.92~20.04.1

This is not a regression as we didn't test ubuntu_bpf on this kernel before.

Test build failed with:
    CLNG-BPF [test_maps] test_global_func13.o
    CLNG-BPF [test_maps] test_cls_redirect_subprogs.o
    CLNG-BPF [test_maps] test_overhead.o
    CLNG-BPF [test_maps] timer_mim.o
  make[1]: Leaving directory '/home/ubuntu/autotest/client/tmp/ubuntu_bpf/src/linux/tools/testing/selftests/bpf'
  make: Leaving directory '/home/ubuntu/autotest/client/tmp/ubuntu_bpf/src/linux/tools/testing/selftests'
  stderr:
  Warning: Kernel ABI header at 'tools/include/uapi/linux/bpf.h' differs from latest version at 'include/uapi/linux/bpf.h'
  Warning: Kernel ABI header at 'tools/include/uapi/linux/netlink.h' differs from latest version at 'include/uapi/linux/netlink.h'
  Warning: Kernel ABI header at 'tools/include/uapi/linux/if_link.h' differs from latest version at 'include/uapi/linux/if_link.h'
  In file included from progs/timer_mim.c:7:
  /home/ubuntu/autotest/client/tmp/ubuntu_bpf/src/linux/tools/testing/selftests/bpf/bpf_tcp_helpers.h:24:18: warning: unknown attribute 'preserve_access_index' ignored [-Wunknown-attributes]
  } __attribute__((preserve_access_index));
                   ^
  /home/ubuntu/autotest/client/tmp/ubuntu_bpf/src/linux/tools/testing/selftests/bpf/bpf_tcp_helpers.h:37:18: warning: unknown attribute 'preserve_access_index' ignored [-Wunknown-attributes]
  } __attribute__((preserve_access_index));
                   ^
  /home/ubuntu/autotest/client/tmp/ubuntu_bpf/src/linux/tools/testing/selftests/bpf/bpf_tcp_helpers.h:41:18: warning: unknown attribute 'preserve_access_index' ignored [-Wunknown-attributes]
  } __attribute__((preserve_access_index));
                   ^
  /home/ubuntu/autotest/client/tmp/ubuntu_bpf/src/linux/tools/testing/selftests/bpf/bpf_tcp_helpers.h:52:18: warning: unknown attribute 'preserve_access_index' ignored [-Wunknown-attributes]
  } __attribute__((preserve_access_index));
                   ^
  /home/ubuntu/autotest/client/tmp/ubuntu_bpf/src/linux/tools/testing/selftests/bpf/bpf_tcp_helpers.h:56:18: warning: unknown attribute 'preserve_access_index' ignored [-Wunknown-attributes]
  } __attribute__((preserve_access_index));
                   ^
  /home/ubuntu/autotest/client/tmp/ubuntu_bpf/src/linux/tools/testing/selftests/bpf/bpf_tcp_helpers.h:84:18: warning: unknown attribute 'preserve_access_index' ignored [-Wunknown-attributes]
  } __attribute__((preserve_access_index));
                   ^
  /home/ubuntu/autotest/client/tmp/ubuntu_bpf/src/linux/tools/testing/selftests/bpf/bpf_tcp_helpers.h:133:18: warning: unknown attribute 'preserve_access_index' ignored [-Wunknown-attributes]
  } __attribute__((preserve_access_index));
                   ^
  /home/ubuntu/autotest/client/tmp/ubuntu_bpf/src/linux/tools/testing/selftests/bpf/bpf_tcp_helpers.h:149:18: warning: unknown attribute 'preserve_access_index' ignored [-Wunknown-attributes]
  } __attribute__((preserve_access_index));
                   ^
  /home/ubuntu/autotest/client/tmp/ubuntu_bpf/src/linux/tools/testing/selftests/bpf/bpf_tcp_helpers.h:208:11: error: use of unknown builtin '__builtin_preserve_field_info' [-Wimplicit-function-declaration]
          return !!BPF_CORE_READ_BITFIELD(tp, is_cwnd_limited);
                   ^
  /home/ubuntu/autotest/client/tmp/ubuntu_bpf/src/linux/tools/testing/selftests/bpf/tools/include/bpf/bpf_core_read.h:88:36: note: expanded from macro 'BPF_CORE_READ_BITFIELD'
          const void *p = (const void *)s + __CORE_RELO(s, field, BYTE_OFFSET); \
                                            ^
  /home/ubuntu/autotest/client/tmp/ubuntu_bpf/src/linux/tools/testing/selftests/bpf/tools/include/bpf/bpf_core_read.h:41:2: note: expanded from macro '__CORE_RELO'
          __builtin_preserve_field_info((src)->field, BPF_FIELD_##info)
          ^
  8 warnings and 1 error generated.
  make[1]: *** [Makefile:470: /home/ubuntu/autotest/client/tmp/ubuntu_bpf/src/linux/tools/testing/selftests/bpf/timer_mim.o] Error 1
  make: *** [Makefile:171: all] Error 2

[Po-Hsu Lin (cypressyew)]

Error message on F-hwe-5.15 ARM64

 [stdout] CLNG-BPF [test_maps] tailcall3.o
 [stdout] CLNG-BPF [test_maps] freplace_global_func.o
 [stdout] CLNG-BPF [test_maps] btf__core_reloc_nesting___err_missing_container.o
 [stdout] CLNG-BPF [test_maps] btf_dump_test_case_packing.o
 [stdout] CLNG-BPF [test_maps] test_endian.o
 [stderr] In file included from progs/test_endian.c:4:
 [stderr] /home/ubuntu/autotest/client/tmp/ubuntu_bpf/src/linux/tools/testing/selftests/bpf/tools/include/vmlinux.h:5:15: error: attribute 'preserve_access_index' is not supported by '#pragma clang attribute'
 [stderr] #pragma clang attribute push (__attribute__((preserve_access_index)), apply_to = record)
 [stderr] ^
 [stderr] /home/ubuntu/autotest/client/tmp/ubuntu_bpf/src/linux/tools/testing/selftests/bpf/tools/include/vmlinux.h:160504:15: error: '#pragma clang attribute pop' with no matching '#pragma clang attribute push'
 [stderr] #pragma clang attribute pop
 [stderr] ^
 [stderr] 2 errors generated.
 [stderr] make[1]: *** [Makefile:470: /home/ubuntu/autotest/client/tmp/ubuntu_bpf/src/linux/tools/testing/selftests/bpf/test_endian.o] Error 1
 [stdout] make[1]: Leaving directory '/home/ubuntu/autotest/client/tmp/ubuntu_bpf/src/linux/tools/testing/selftests/bpf'
 [stdout] make: Leaving directory '/home/ubuntu/autotest/client/tmp/ubuntu_bpf/src/linux/tools/testing/selftests'
 [stderr] make: *** [Makefile:171: all] Error 2

[Po-Hsu Lin (cypressyew)]

Tested with different clang / llvm available on Focal:
clang-10 and llvm-10, test build will fail with:
    CLNG-BPF [test_maps] pyperf600.o
    CLNG-BPF [test_maps] profiler2.o
    CLNG-BPF [test_maps] test_pe_preserve_elems.o
    CLNG-BPF [test_maps] atomics.o
  make[1]: Leaving directory '/home/ubuntu/autotest/client/tmp/ubuntu_bpf/src/linux/tools/testing/selftests/bpf'
  make: Leaving directory '/home/ubuntu/autotest/client/tmp/ubuntu_bpf/src/linux/tools/testing/selftests'
  stderr:
  Warning: Kernel ABI header at 'tools/include/uapi/linux/bpf.h' differs from latest version at 'include/uapi/linux/bpf.h'
  Warning: Kernel ABI header at 'tools/include/uapi/linux/netlink.h' differs from latest version at 'include/uapi/linux/netlink.h'
  Warning: Kernel ABI header at 'tools/include/uapi/linux/if_link.h' differs from latest version at 'include/uapi/linux/if_link.h'
  fatal error: error in backend: line 27: Invalid usage of the XADD return value
  Stack dump:
  0. Program arguments: clang-10 -g -D__TARGET_ARCH_x86 -mlittle-endian -I/home/ubuntu/autotest/client/tmp/ubuntu_bpf/src/linux/tools/testing/selftests/bpf/tools/include -I/home/ubuntu/autotest/client/tmp/ubuntu_bpf/src/linux/tools/testing/selftests/bpf -I/home/ubuntu/autotest/client/tmp/ubuntu_bpf/src/linux/tools/include/uapi -I/home/ubuntu/autotest/client/tmp/ubuntu_bpf/src/linux/tools/testing/selftests/usr/include -idirafter /usr/local/include -idirafter /usr/lib/llvm-10/lib/clang/10.0.0/include -idirafter /usr/include/x86_64-linux-gnu -idirafter /usr/include -Wno-compare-distinct-pointer-types -DENABLE_ATOMICS_TESTS -O2 -target bpf -c progs/atomics.c -o /home/ubuntu/autotest/client/tmp/ubuntu_bpf/src/linux/tools/testing/selftests/bpf/atomics.o -mcpu=v3
  1. <eof> parser at end of file
  2. Code generation
  3. Running pass 'Function Pass Manager' on module 'progs/atomics.c'.
  4. Running pass 'BPF PreEmit Checking' on function '@add'
  /lib/x86_64-linux-gnu/libLLVM-10.so.1(_ZN4llvm3sys15PrintStackTraceERNS_11raw_ostreamE+0x1f)[0x7f66edf4d4ff]
  /lib/x86_64-linux-gnu/libLLVM-10.so.1(_ZN4llvm3sys17RunSignalHandlersEv+0x50)[0x7f66edf4b7b0]

clang-11 and llvm-11, test build will fail with:
    CLNG-BPF [test_maps] test_l4lb.o
    CLNG-BPF [test_maps] pyperf600.o
    CLNG-BPF [test_maps] profiler2.o
    CLNG-BPF [test_maps] test_pe_preserve_elems.o
    CLNG-BPF [test_maps] atomics.o
  make[1]: Leaving directory '/home/ubuntu/autotest/client/tmp/ubuntu_bpf/src/linux/tools/testing/selftests/bpf'
  make: Leaving directory '/home/ubuntu/autotest/client/tmp/ubuntu_bpf/src/linux/tools/testing/selftests'
  stderr:
  Warning: Kernel ABI header at 'tools/include/uapi/linux/bpf.h' differs from latest version at 'include/uapi/linux/bpf.h'
  Warning: Kernel ABI header at 'tools/include/uapi/linux/netlink.h' differs from latest version at 'include/uapi/linux/netlink.h'
  Warning: Kernel ABI header at 'tools/include/uapi/linux/if_link.h' differs from latest version at 'include/uapi/linux/if_link.h'
  fatal error: error in backend: line 27: Invalid usage of the XADD return value
  PLEASE submit a bug report to https://bugs.llvm.org/ and include the crash backtrace, preprocessed source, and associated ru...

[Po-Hsu Lin (cypressyew)]

OK I noticed that clang-13 is available in focal-proposed universe, and with this version the test can be built.

Since we don't enable -proposed for SRU now, and this package has already stayed in -proposed since 2022-07-15. Looks like it's unlikely to get promoted to -updates.