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_fchmodat, "fchmodat"},
    {__NR_fchown, "fchown"},
    {__NR_fchownat, "fchownat"},
    {__NR_fcntl, "fcntl"},
    {__NR_fdatasync, "fdatasync"},
    {__NR_fgetxattr, "fgetxattr"},
    {__NR_finit_module, "finit_module"},
    {__NR_flistxattr, "flistxattr"},
    {__NR_flock, "flock"},
    {__NR_fork, "fork"},
    {__NR_fremovexattr, "fremovexattr"},
    {__NR_fsetxattr, "fsetxattr"},
    {__NR_fstat, "fstat"},
    {__NR_fstatfs, "fstatfs"},
    {__NR_fsync, "fsync"},
    {__NR_ftruncate, "ftruncate"},
    {__NR_futex, "futex"},
    {__NR_futimesat, "futimesat"},
    {__NR_get_kernel_syms, "get_kernel_syms"},
    {__NR_get_mempolicy, "get_mempolicy"},
    {__NR_get_robust_list, "get_robust_list"},
    {__NR_get_thread_area, "get_thread_area"},
    {__NR_getcpu, "getcpu"},
    {__NR_getcwd, "getcwd"},
    {__NR_getdents, "getdents"},
    {__NR_getdents64, "getdents64"},
    {__NR_getegid, "getegid"},
    {__NR_geteuid, "geteuid"},
    {__NR_getgid, "getgid"},
    {__NR_getgroups, "getgroups"},