PR_SET_SYSCALL_USER_DISPATCH(2const) PR_SET_SYSCALL_USER_DISPATCH(2const) PR_SET_SYSCALL_USER_DISPATCH - (libc -lc) #include /* PR_* */ #include int prctl(PR_SET_SYSCALL_USER_DISPATCH, long op, ...); int prctl(PR_SET_SYSCALL_USER_DISPATCH, PR_SYS_DISPATCH_ON, unsigned long off, unsigned long size, int8_t *switch); int prctl(PR_SET_SYSCALL_USER_DISPATCH, PR_SYS_DISPATCH_OFF, 0L, 0L, 0L); . . SIGSYS . . PR_SYS_DISPATCH_ON . . off size . ( C.) switch / . SYSCALL_DISPATCH_FILTER_BLOCK SYSCALL_DISPATCH_FILTER_ALLOW . SIGSYS . SIGSYS . siginfo_t ( sigaction(2)) : o si_signo SIGSYS. o si_call_addr . o si_syscall si_arch . o si_code SYS_USER_DISPATCH. o si_errno 0. ( ). . ( ) ucontext . sigaction(2) sigreturn(2) getcontext(3) . PR_SYS_DISPATCH_OFF . fork(2) clone(2) execve(2). 0. -1 errno . EFAULT switch . EINVAL op PR_SYS_DISPATCH_ON . EINVAL op . . x86 . 5.11 (x86). prctl(2) Documentation/admin-guide/ syscall-user-dispatch.rst 3 . . : . 6.18 8 2026 PR_SET_SYSCALL_USER_DISPATCH(2const)