Hey everyone, This is v5 of this patchset. v5 does not introduce any functional changes since none were requested or required in the thread. Instead, it focusses on updated documentation making it very clear what the intentions are how to extend this syscall. Eric, I dragged Serge into this and we went through the mails and tried to very thoroughly address your concerns about whether the width of the target should depend on flags or file descriptor types. As far as we understand from the threads this was your ultimate worry and also the reason why you withheld your agreement to the name of the syscall. We have outlined how the syscall is intended to be extended and decided that flags (e.g. PIDFD_TYPE_TID, PIDFD_TYPE_PGID) are the way to go. In line with this we decided to accept "pidfd_" as prefix for the new syscall. All concerns we could identify and understand we tried to address. I hope this will be sufficient for you to get behind the patch. The relevant section in the commit message is titled: /* sending signals to threads (tid) and process groups (pgid) */ Thanks! Christian Christian Brauner (1): signal: add pidfd_send_signal() syscall arch/x86/entry/syscalls/syscall_32.tbl | 1 + arch/x86/entry/syscalls/syscall_64.tbl | 1 + fs/proc/base.c | 20 +++- include/linux/proc_fs.h | 12 +++ include/linux/syscalls.h | 3 + include/uapi/asm-generic/unistd.h | 4 +- kernel/signal.c | 141 +++++++++++++++++++++++-- 7 files changed, 173 insertions(+), 9 deletions(-) -- 2.19.1