Namespaces exhausted CLONE_XXX bits problem

Cedric Le Goater clg at
Tue Jan 15 00:39:50 PST 2008

Pavel Emelyanov wrote:
> Dave Hansen wrote:
>> On Mon, 2008-01-14 at 16:36 -0500, Oren Laadan wrote:
>>> I second the concern of running out of 64 bits of flags. In fact, the
>>> problem with the flags is likely to be valid outside our context, and
>>> general to the linux kernel soon. Should we not discuss it there
>>> too ? 
>> It would be pretty easy to make a new one expandable:
>> 	sys_newclone(int len, unsigned long *flags_array)
>> Then you could give it a virtually unlimited number of "unsigned long"s
>> pointed to by "flags_array".
>> Plus, the old clone just becomes:
>>         sys_oldclone(unsigned long flags)
>>         {
>>         	do_newclone(1, &flags);
>>         }
>> We could validate the flags array address in sys_newclone(), then call
>> do_newclone().
> Hmm. I have an idea how to make this w/o a new system call. This might
> look wierd, but. Why not stopple the last bit with a CLONE_NEWCLONE and
> consider the parent_tidptr/child_tidptr in this case as the pointer to 
> an array of extra arguments/flargs?

It's a bit hacky but it looks like a good idea to me !

Shall we use parent_tidptr or child_tidptr to pass a extended array of 
flags only ? if we could pass the pid of the task to be cloned, it would 
be useful for c/r.


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