Re: 64bit startup

[Sergey Bugaev]

On Fri, May 26, 2023 at 2:15 PM Samuel Thibault <samuel.thibault@gnu.org> wrote:
> It does load, but stays stuck when starting ext2fs:
>
>    start ext2fs:

Yes, I can reproduce this with your build of ext2fs.static

Unfortunately there are no symbols (maybe you could teach me how to
fetch and load separate debuginfo into gdb?), but it's crashing on:

   0x000000000055cd00: push   %rbp
   0x000000000055cd01: mov    %esi,%eax
   0x000000000055cd03: mov    %rdx,%rsi
   0x000000000055cd06: mov    %rsp,%rbp
   0x000000000055cd09: push   %r13
   0x000000000055cd0b: push   %r12
   0x000000000055cd0d: push   %rbx
   0x000000000055cd0e: sub    $0x1048,%rsp
=> 0x000000000055cd15: mov    %fs:0x28,%rdx

(gdb) p $fs_base
$2 = 0

%fs:0x28 is tcb->stack_guard. The function is thread_set_state, I
believe -- it's trying to set this very fs_base to the
__init1_tcbhead. Clearly it gets built with the stack guard in
your/Debian build, but not in mine or Flavio's.

> BTW, it seems the control-alt-d kdb shortcut is not working?

I didn't enable kdb in my gnumach build. I never learned how to use it.

Sergey