selftests/net/bpf - Failure in building bpf program on G/RISC-V (kernel 5.8)

I found the following failure in G/RISC-V, cycle sru-20210510 :

21:07:11 ERROR| [stderr] progs/test_vmlinux.c:24:18: error: use of undeclared identifier '__NR_nanosleep'
21:07:11 ERROR| [stderr] if (args->id != __NR_nanosleep)
21:07:11 ERROR| [stderr] ^
[...]
21:07:11 ERROR| [stderr] progs/test_vmlinux.c:60:12: error: use of undeclared identifier '__NR_nanosleep'
21:07:11 ERROR| [stderr] if (id != __NR_nanosleep)
21:07:11 ERROR| [stderr] ^
21:07:11 ERROR| [stderr] progs/test_vmlinux.c:63:15: warning: implicit declaration of function 'PT_REGS_PARM1_CORE' is invalid in C99 [-Wimplicit-function-declaration]
21:07:11 ERROR| [stderr] ts = (void *)PT_REGS_PARM1_CORE(regs);
21:07:11 ERROR| [stderr] ^
[...]
/home/ubuntu/autotest/client/tmp/ubuntu_kernel_selftests/src/linux/tools/testing/selftests/bpf/tools/include/bpf/bpf_tracing.h:298:29: note: expanded from macro '___bpf_concat'
21:07:12 ERROR| [stderr] #define ___bpf_concat(a, b) a ## b
21:07:12 ERROR| [stderr] ^
21:07:12 ERROR| [stderr] <scratch space>:28:1: note: expanded from here
21:07:12 ERROR| [stderr] ___bpf_kprobe_args3
21:07:12 ERROR| [stderr] ^
21:07:12 ERROR| [stderr] /home/ubuntu/autotest/client/tmp/ubuntu_kernel_selftests/src/linux/tools/testing/selftests/bpf/tools/include/bpf/bpf_tracing.h:359:29: note: expanded from macro '___bpf_kprobe_args3'
21:07:12 ERROR| [stderr] ___bpf_kprobe_args2(args), (void *)PT_REGS_PARM3(ctx)
21:07:12 ERROR| [stderr] ^~~~~~~~~~~~~~~~~~~~~~~~~~
21:07:12 ERROR| [stderr] 10 warnings and 3 errors generated.
21:07:12 ERROR| [stderr] llc: error: llc: <stdin>:1:1: error: expected top-level entity
21:07:12 ERROR| [stderr] BPF obj compilation failed
21:07:12 ERROR| [stderr] ^
21:07:12 ERROR| [stderr] make[1]: *** [Makefile:376: /home/ubuntu/autotest/client/tmp/ubuntu_kernel_selftests/src/linux/tools/testing/selftests/bpf/test_vmlinux.o] Error 1
21:07:12 ERROR| [stderr] make: *** [Makefile:159: all] Error 2
21:07:12 ERROR| Exception escaping from test:
Traceback (most recent call last):
  File "/home/ubuntu/autotest/client/shared/test.py", line 411, in _exec
    _call_test_function(self.execute, *p_args, **p_dargs)
  File "/home/ubuntu/autotest/client/shared/test.py", line 823, in _call_test_function
    return func(*args, **dargs)
  File "/home/ubuntu/autotest/client/shared/test.py", line 291, in execute
    postprocess_profiled_run, args, dargs)
  File "/home/ubuntu/autotest/client/shared/test.py", line 212, in _call_run_once
    self.run_once(*args, **dargs)
  File "/home/ubuntu/autotest/client/tests/ubuntu_kernel_selftests/ubuntu_kernel_selftests.py", line 239, in run_once
    utils.system(cmd)
  File "/home/ubuntu/autotest/client/shared/utils.py", line 1232, in system
    verbose=verbose).exit_status
  File "/home/ubuntu/autotest/client/shared/utils.py", line 918, in run
    "Command returned non-zero exit status")
CmdError: Command <make -C linux/tools/testing/selftests TARGETS=bpf SKIP_TARGETS= KDIR=/usr/src/linux-headers-5.8.0-26-generic> failed, rc=2, Command returned non-zero exit status
* Command:
    make -C linux/tools/testing/selftests TARGETS=bpf SKIP_TARGETS=
    KDIR=/usr/src/linux-headers-5.8.0-26-generic
Exit status: 2

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