Re: [RFC] more close_range() fun

[Al Viro <viro@zeniv.linux.org.uk>]

On Fri, Aug 16, 2024 at 10:25:52AM +0200, Christian Brauner wrote:

> I don't think so. It is clear that the file descriptor table is unshared
> and that fds are closed afterwards and that this can race with file
> descriptors being inserted into the currently shared fdtable. Imho,
> there's nothing to fix here.
> 
> I also question whether any userspace out there has any such ordering
> expectations between the two dup2()s and the close_range() call and
> specifically whether we should even bother giving any such guarantees.

Huh?

It's not those dup2() vs unsharing; it's relative order of those dup2().

Hell, make that

	dup2(0, 1023);
	dup2(1023, 10);

Do you agree that asynchronous code observing 10 already open, but 1023
still not open would be unexpected?