Re: [PATCH 1/2] fork: add clone6

On Tue, May 28, 2019 at 3:08 AM Christian Brauner [off-list ref] wrote:

On Mon, May 27, 2019 at 12:27:08PM -0700, Linus Torvalds wrote:

quoted

On Mon, May 27, 2019 at 3:42 AM Christian Brauner [off-list ref] wrote:

quoted

Hm, still pondering whether having one unsigned int argument passed
through registers that captures all the flags from the old clone() would
be a good idea.

That sounds like a reasonable thing to do.

Maybe we could continue to call the old flags CLONE_XYZ and continue
to pass them in as "flags" argument, and then we have CLONE_EXT_XYZ
flags for a new 64-bit flag field that comes in through memory in the
new clone_args thing?

Hm. I think I'll try a first version without an additional register
flags argument. And here's why: I'm not sure it buys us a lot especially
if we're giving up on making this convenient for seccomp anyway.
And with that out of the way (at least for the moment) I would really
like to make this interface consistent. But we can revisit this when I
have the code.

Seems reasonable.  Once the interface is nailed down, we can see if it
makes sense to break out some flags into a register.  I would guess
that all the unsharing flags are a good candidate.