> On Jan 11, 2021, at 13:06, Andy Lutomirski <l...@amacapital.net> wrote:
>
>> On Jan 11, 2021, at 12:00 PM, Borislav Petkov <b...@alien8.de> wrote:
>>
>> Or do you mean I should add "unsafe_fsgsbase" to grub cmdline and bisect
>> with fsgsbase enabled in all test kernels?
>
> Yes. But I can also look myself in a bit.
I was able to find this patch in that way:
commit 0bf7e460361c703333f3a82e50e7871465fe20f9
Author: Andy Lutomirski <l...@kernel.org>
Date: Thu May 28 16:13:51 2020 -0400
x86/process/64: Use FSBSBASE in switch_to() if available
The GDB behavior looks to be different between the two cases -- with vs
without gdb server, when I checked the GS/GSBASE values on the ptrace front.
It set the correct GSBASE (e.g.,=0xf7fcf0c0) of GS=0x63 without running the
server. But GSBASE=0 with the server. When I forced to set the correct base,
it exited normally.
Thanks,
Chang
