On 04/18, Christian Brauner wrote: > > @@ -1674,13 +1729,14 @@ static __latent_entropy struct task_struct *copy_process( > unsigned long clone_flags, > unsigned long stack_start, > unsigned long stack_size, > + int __user *parent_tidptr, > int __user *child_tidptr, > struct pid *pid, > int trace, > unsigned long tls, > int node) > { > - int retval; > + int pidfd = -1, retval; it seems that initialization is unneeded, but this is cosmetic. I see no technical problems, feel free to add my reviewed-by. But let me ask a couple of questions... Why O_CLOEXEC? I am just curious, I do not really care. Should we allow CLONE_THREAD | CLONE_PIDFD ? Are you sure we will never need to extend this interface? If not, then perhaps it make sense to add something like if (CLONE_PIDFD) { unsigned long not_used_yet; if (get_user(not_used_yet, parent_tidptr) || not_used_yet != 0) return -EINVAL; } this way we can easily add more arguments in future or even turn CLONE_PIDFD into CLONE_MORE_ARGS_IN_PARENT_TIDPTR. Not that I think this is really good idea, sys_clone2() makes more sense, but still. Oleg.