I'm debugging an ELF 64-bit binary using gdb
and I notice that the %fs
register is set to 0x63
. For some testing that I'd like to perform I'd like to set the %fs
register to 0x00
.
I tried doing a set $fs=0x0
but the value wouldn't change. In some cases I got a:
Couldn't write registers: Input/output error.
Is there any way I could set the value for the %fs
register? I'm also open to modifying the binary, adding inline assembly to the source, etc.
EDIT : Currently, I'm trying this out by attaching to a process rather than running it from within gdb
.
A screenshot to illustrate the problem :