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_putpmsg, "putpmsg"},
    {__NR_pwrite64, "pwrite64"},
    {__NR_pwritev, "pwritev"},
#ifdef __NR_pwritev2
    {__NR_pwritev2, "pwritev2"},
#endif
    {__NR__sysctl, "_sysctl"},
    {__NR_query_module, "query_module"},
    {__NR_quotactl, "quotactl"},
    {__NR_read, "read"},
    {__NR_readahead, "readahead"},
    {__NR_readlink, "readlink"},
    {__NR_readlinkat, "readlinkat"},
    {__NR_readv, "readv"},
    {__NR_reboot, "reboot"},
    {__NR_recvfrom, "recvfrom"},
    {__NR_recvmmsg, "recvmmsg"},
    {__NR_recvmsg, "recvmsg"},
    {__NR_remap_file_pages, "remap_file_pages"},
    {__NR_removexattr, "removexattr"},
    {__NR_rename, "rename"},
    {__NR_renameat, "renameat"},
    {__NR_renameat2, "renameat2"},
    {__NR_request_key, "request_key"},
    {__NR_restart_syscall, "restart_syscall"},
    {__NR_rmdir, "rmdir"},
    {__NR_rt_sigaction, "rt_sigaction"},
    {__NR_rt_sigpending, "rt_sigpending"},
    {__NR_rt_sigprocmask, "rt_sigprocmask"},
    {__NR_rt_sigqueueinfo, "rt_sigqueueinfo"},