Re: [PATCH 0/4] MR6866: Draft: ntdll: On macOS x86_64, swap GSBASE between the TEB and macOS TSD when entering/leaving PE code.

[Alexandre Julliard (＠julliard)]

> If a signal is delivered in `__wine_syscall_dispatcher_return` after the `_thread_set_tsd_base` call (setting GSBASE back to the TEB) but before switching back to the user stack, GSBASE needs to be reset to the TEB even though `is_inside_syscall()` is still TRUE. Rather than the `gs30` trick, maybe this could be detected by putting a label at the stack switch and then checking whether `RIP` is between `__wine_syscall_dispatcher_return` or the stack switch?

That's handled by making the stack pointer point inside the frame, which causes `is_inside_syscall` to return FALSE. As long as you do it at the same place as the Linux case it should work fine.