Re: [musl] Re: add loongarch64 port

[Christian Brauner <brauner@kernel.org>]

On Sun, Apr 10, 2022 at 12:30:59PM +0200, Arnd Bergmann wrote:
> On Sat, Apr 9, 2022 at 3:31 PM Rich Felker <dalias@libc.org> wrote:
> >
> > Actually, if there aren't yet archs lacking SYS_clone, this API
> > regression may be a good argument not to drop SYS_clone on new archs
> > yet until there's a way for new archs to get the same behavior
> > (unspecified stack size).
> 
> That is a good point, but it also appears that the behavior of
> clone3() is unintentional
> here, I'm fairly sure it was meant to be a drop-in replacement for clone() with
> additional features.

Mostly but not in all ways. We did decide it's ok to make API
improvements that might break compatibility with legacy clone().

> 
> Not sure what the best fix for this is, as the check for size==0 was clearly
> intentional, but seems to prevent this from working. A special flag to ignore
> the size, or a magic size value like -1ull might work, but neither of them
> is a great interface.

Can someone explain the use-case in a bit more detail, please?

If it is a legitimate use-case that callers need to be able to pass a
stack and have no way of also passing a size then we should just remove
the size == 0 check for all architectures that don't have a hard
requirement on passing a size together with the stack pointer.

Wdyt, Arnd?