The 05/23/2023 15:09, Catalin Marinas wrote: > At least for glibc, it seems that there is a conversion to unsigned > long: > > https://sourceware.org/git/?p=glibc.git;a=blob;f=sysdeps/unix/sysv/linux/prctl.c#l28 > > unsigned long int arg2 = va_arg (arg, unsigned long int); > > (does va_arg expand to an actual cast?) this is not a conversion. at this point the argument is already corrupt since an int was passed instead of unsigned long, usually it's just wrong top 32bit, but in theory arg passing for int and long could be completely different. > > If the libc passes a 32-bit to a kernel ABI that expects 64-bit, I think > it's a user-space bug and not a kernel ABI issue. this is point 3 in an earlier mail i wrote about varargs (we ran into vararg issues during morello porting but it affects all 64bit targets): https://lkml.org/lkml/2022/10/31/386 IMPORTANT NOTICE: The contents of this email and any attachments are confidential and may also be privileged. If you are not the intended recipient, please notify the sender immediately and do not disclose the contents to any other person, use it for any purpose, or store or copy the information in any medium. Thank you.
