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_mknod, "mknod"},
    {__NR_mknodat, "mknodat"},
    {__NR_mlock, "mlock"},
    {__NR_mlock2, "mlock2"},
    {__NR_mlockall, "mlockall"},
    {__NR_mmap, "mmap"},
    {__NR_modify_ldt, "modify_ldt"},
    {__NR_mount, "mount"},
    {__NR_move_pages, "move_pages"},
    {__NR_mprotect, "mprotect"},
    {__NR_mq_getsetattr, "mq_getsetattr"},
    {__NR_mq_notify, "mq_notify"},
    {__NR_mq_open, "mq_open"},
    {__NR_mq_timedreceive, "mq_timedreceive"},
    {__NR_mq_timedsend, "mq_timedsend"},
    {__NR_mq_unlink, "mq_unlink"},
    {__NR_mremap, "mremap"},
    {__NR_msgctl, "msgctl"},
    {__NR_msgget, "msgget"},
    {__NR_msgrcv, "msgrcv"},
    {__NR_msgsnd, "msgsnd"},
    {__NR_msync, "msync"},
    {__NR_munlock, "munlock"},
    {__NR_munlockall, "munlockall"},
    {__NR_munmap, "munmap"},
    {__NR_name_to_handle_at, "name_to_handle_at"},
    {__NR_nanosleep, "nanosleep"},
    {__NR_newfstatat, "newfstatat"},
    {__NR_nfsservctl, "nfsservctl"},
    {__NR_open, "open"},