> arch/x86/entry/syscalls/syscall_32.tbl | 1 + > arch/x86/entry/syscalls/syscall_64.tbl | 1 + > include/linux/syscalls.h | 2 + > include/uapi/asm-generic/unistd.h | 4 +- When you add a new system call, please add it to all architectures. See the patches for the last few additions on how to do it, in particular the bit around adding the arm64 compat entry that is a bit tricky. It may be best to split out the patch changing all architectures from the one adding the new syscall. > +SYSCALL_DEFINE5(pidfd_ptrace, int, pidfd, long, request, unsigned long, addr, > + unsigned long, data, unsigned int, flags) > +{ When you add a new variant of ptrace, there also needs to be the corresponding COMPAT_SYSCLAL_DEFINE5(...) calling compat_ptrace_request(). If you want, you could unify the native and compat code paths more by merging compat_ptrace_request() into ptrace_request() and using in_compat_syscall() checks for the ones that are different. This also would best be done as a separate cleanup patch upfront. Arnd