On Mon, Feb 02, 2026 at 11:54:17PM +0100, Arnd Bergmann wrote: > On Mon, Feb 2, 2026, at 17:45, Michael S. Tsirkin wrote: > > On Mon, Feb 02, 2026 at 12:59:03PM +0100, Arnd Bergmann wrote: > > > > I think .compat_ioctl would be cleaner frankly. Just look at > > all the ifdefery. And who knows what broken-ness userspace > > comes up with with this approach. Better use the standard approach. > > Sent now. > > I'm not sure it's much better because there is quite a bit of > code duplication, and reducing that would be a larger rework.
yes but on the flip side, we can put it all inside ifdef CONFIG_COMPAT (which this code did not do, but should IMHO). > It may be best to hold off on patch 2 for the coming merge window > since the compat ioctl code has apparently always been broken for > x86 here. And it needs testing. > I hope we can at least get patch 1/2 merged along with the > new code though, otherwise it would get a lot harder to sort > it out properly, with the v2 struct members overlapping the > old padding fields. > > Arnd Along with it or no, surely before the release. Given 32 on 64 with this apparently has been broken forever, I will merge this just based on even you did not bother testing compat, I am inclined to say I am merging this but not rebasing because of this. Oh and we got lucky this didn't leak kernel stack info. Eugenio, note for the future: please help make sure UAPI structs do not have hidden padding. -- MST
