On Mon, May 18, 2026 at 01:22:19PM -0700, H. Peter Anvin wrote: > On May 17, 2026 11:30:21 AM PDT, Richard Patel <[email protected]> wrote: > >IBT is not implemented for 32-bit and cannot be enabled using a > >32-bit syscall. However, a 64-bit thread could far jump into 32-bit. > >Therefore, 32-bit sigreturn must be banned until IBT supports that > >environment. > Dumb question: is there any reason not to just enable it for 32 bits? It > doesn't seem that it would be that big of a delta to Just Do It.™ > > That being said, I suspect the number of users will be very small if any.
Yes, partially, good call. It'd be tricky for legacy IA32 signals. sigframe_ia32 would need to be modified I think. For rt_sigframe_ia32 (rt_sigreturn) we can put it in ucontext_ia32::uc_flags. I'll fix it in v2 later this week and add tests.
