On Fri, Oct 8, 2021 at 2:06 PM Rich Felker <dalias@xxxxxxxx> wrote: > On Fri, Oct 08, 2021 at 11:24:39AM +0200, Arnd Bergmann wrote: > > > > I've tried to understand this part of musl's convert_ioctl_struct(), but I just > > can't figure out whether it does the conversion based the on the layout that > > is currently used in the kernel, or based on the layout we should have been > > using, and would use with the above fix. Rich, can you help me here? > > If the attempted 64-bit ioctl is missing (ENOTTY), it does the > conversion to the legacy 32-bit one and retries with that, then > converts the results back to the 64-bit form. I understand that it tries to do that. The part that I'm not sure about is which of the two possible 64-bit forms it's using -- the broken one we have defined in the kernel headers, or the one we were trying to define but failed. Arnd