Force software breakpoint on read-only memory

[Mathieu Tarral <mathieu dot tarral at protonmail dot com>]

Hi,

I'm trying to set a software breakpoint on a read-only memory page.
GDB automatically sets the breakpoint as hardware, but I would like to
keep using software breakpoints.

I found the `set breakpoint auto-hw off option in` in the
documentation:
"If the target provides a memory map, GDB will warn when
trying to set software breakpoint at a read-only address."

However, even when I set it, GDB gives me a warning and my command is aborted:

$ gdb -x gdbinit ~/tmp/ntoskrnl.exe
0x80545c9f in ?? ()
(gdb) set breakpoint auto-hw off
(gdb) b NtOpenFile
Breakpoint 1 at 0x4a30b1
(gdb) continue
Continuing.
Warning:
Cannot insert breakpoint 1.
Cannot set software breakpoint at read-only address 0x4a30b1

Command aborted.
(gdb)



My stub interacts directly with the guest hardware, from the
hypervisor, so I can bypass the read-only protections.
That's why i wanted to force the software breakpoint
and ignore the memory map.

Is this a bug in GDB ?

Thanks !
--
Mathieu Tarral

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