It doesn't even specify which "invalid syscall".
```
$ src/bitcoind -sandbox=log-and-abort
2022-02-17T13:45:57Z Bitcoin Core version v22.99.0-b223c3c21e89 (release build)
2022-02-17T13:45:57Z Assuming ancestors of block 00000000000000000008a89e854d57e5667df88f1cdef6fde2fbca1de5b639ad have valid signatures.
2022-02-17T13:45:57Z Setting nMinimumChainWork=00000000000000000000000000000000000000001fa4663bbbe19f82de910280
2022-02-17T13:45:57Z Experimental syscall sandbox enabled (-sandbox=log-and-abort): bitcoind will terminate if an unexpected (not allowlisted) syscall is invoked.
2022-02-17T13:45:57Z Using the 'sse4(1way),sse41(4way),avx2(8way)' SHA256 implementation
2022-02-17T13:45:57Z Default data directory /…/.bitcoin
2022-02-17T13:45:57Z Using data directory /…/.bitcoin
2022-02-17T13:45:57Z Config file: /…/.bitcoin/bitcoin.conf (not found, skipping)
2022-02-17T13:45:57Z Command-line arg: sandbox="log-and-abort"
2022-02-17T13:45:57Z Using at most 125 automatic connections (1024 file descriptors available)
2022-02-17T13:45:57Z Using 16 MiB out of 32/2 requested for signature cache, able to store 524288 elements
2022-02-17T13:45:57Z Using 16 MiB out of 32/2 requested for script execution cache, able to store 524288 elements
2022-02-17T13:45:57Z Script verification uses 1 additional threads
Bad system call (core dumped)
```
Nothing in `dmesg` either.
{__NR_open_by_handle_at, "open_by_handle_at"},
    {__NR_openat, "openat"},
    {__NR_pause, "pause"},
    {__NR_perf_event_open, "perf_event_open"},
    {__NR_personality, "personality"},
    {__NR_pipe, "pipe"},
    {__NR_pipe2, "pipe2"},
    {__NR_pivot_root, "pivot_root"},
#ifdef __NR_pkey_alloc
    {__NR_pkey_alloc, "pkey_alloc"},
#endif
#ifdef __NR_pkey_free
    {__NR_pkey_free, "pkey_free"},
#endif
#ifdef __NR_pkey_mprotect
    {__NR_pkey_mprotect, "pkey_mprotect"},
#endif
    {__NR_poll, "poll"},
    {__NR_ppoll, "ppoll"},
    {__NR_prctl, "prctl"},
    {__NR_pread64, "pread64"},
    {__NR_preadv, "preadv"},
#ifdef __NR_preadv2
    {__NR_preadv2, "preadv2"},
#endif
    {__NR_prlimit64, "prlimit64"},
    {__NR_process_vm_readv, "process_vm_readv"},
    {__NR_process_vm_writev, "process_vm_writev"},
    {__NR_pselect6, "pselect6"},
    {__NR_ptrace, "ptrace"},