Pavel Emelyanov wrote:
> No, switch_task_namespaces is the wrong place to do this. It is to be 
> done in copy_ipc_ns. If you need a task for which a new namespace is 
> being prepared, then pass one into it.
>
>   
copy_ipc_ns() is also the wrong place:
There are calls after copy_ipc_ns() that can fail (e.g. copy_pid_ns()), 
and if they fail, then the whole syscall is aborted.
But undoing outstanding semaphore operations cannot be undone.
Or simpler: the copy_whatever() functions do not modify current.

Another option would be within sys_unshare():
sys_unshare() first creates all new pointers, and then actual unsharing 
is performed.

What do you think? I that the right place? The implementation could be 
moved into a seperate function, perhaps some of the NULL tests are 
superflous, too.

--
    Manfred