SIGSYS
"Signal system call"
The SIGSYS signal is sent to a process when it passes a bad argument to a system call. In practice, this kind of signal is rarely encountered since applications rely on libraries (e.g. libc) to make the call for them. SIGSYS can be received by applications violating the Linux Seccomp security rules configured to restrict them. SIGSYS can also be used to emulate foreign system calls, e.g. emulate Windows system calls on Linux.[19]