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_set_tid_address, "set_tid_address"},
    {__NR_setdomainname, "setdomainname"},
    {__NR_setfsgid, "setfsgid"},
    {__NR_setfsuid, "setfsuid"},
    {__NR_setgid, "setgid"},
    {__NR_setgroups, "setgroups"},
    {__NR_sethostname, "sethostname"},
    {__NR_setitimer, "setitimer"},
    {__NR_setns, "setns"},
    {__NR_setpgid, "setpgid"},
    {__NR_setpriority, "setpriority"},
    {__NR_setregid, "setregid"},
    {__NR_setresgid, "setresgid"},
    {__NR_setresuid, "setresuid"},
    {__NR_setreuid, "setreuid"},
    {__NR_setrlimit, "setrlimit"},
    {__NR_setsid, "setsid"},
    {__NR_setsockopt, "setsockopt"},
    {__NR_settimeofday, "settimeofday"},
    {__NR_setuid, "setuid"},
    {__NR_setxattr, "setxattr"},
    {__NR_shmat, "shmat"},
    {__NR_shmctl, "shmctl"},
    {__NR_shmdt, "shmdt"},
    {__NR_shmget, "shmget"},
    {__NR_shutdown, "shutdown"},
    {__NR_sigaltstack, "sigaltstack"},
    {__NR_signalfd, "signalfd"},
    {__NR_signalfd4, "signalfd4"},
    {__NR_socket, "socket"},