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.
{
        allowed_syscalls.insert(__NR_accept);     
        allowed_syscalls.insert(__NR_accept4);    
        allowed_syscalls.insert(__NR_bind);       
        allowed_syscalls.insert(__NR_connect);    
        allowed_syscalls.insert(__NR_listen);     
        allowed_syscalls.insert(__NR_setsockopt); 
        allowed_syscalls.insert(__NR_socket);     
        allowed_syscalls.insert(__NR_socketpair); 
    }
    void AllowNetworkSocketInformation()
    {
        allowed_syscalls.insert(__NR_getpeername); 
        allowed_syscalls.insert(__NR_getsockname); 
        allowed_syscalls.insert(__NR_getsockopt);  
    }
    void AllowOperationOnExistingFileDescriptor()
    {
        allowed_syscalls.insert(__NR_close);    
        allowed_syscalls.insert(__NR_dup);      
        allowed_syscalls.insert(__NR_dup2);     
        allowed_syscalls.insert(__NR_fcntl);    
        allowed_syscalls.insert(__NR_shutdown); 
    }
    void AllowPipe()
    {
        allowed_syscalls.insert(__NR_pipe);  
        allowed_syscalls.insert(__NR_pipe2); 
    }
    void AllowPrctl()