Re: [PATCH 3/3] gdbserver/Windows: crash during connection establishment phase

[Pedro Alves <palves@redhat.com>]

On 05/04/2018 07:30 PM, Joel Brobecker wrote:
> On Windows, starting a new process with GDBserver seeems to work,
> in the sense that the program does get started, and GDBserver
> confirms that it is listening for GDB to connect. However, as soon as
> GDB establishes the connection with GDBserver, and starts discussing
> with it, GDBserver crashes, with a SEGV.
> 
> This SEGV occurs in remote-utils.c::prepare_resume_reply...
> 
>   | regp = current_target_desc ()->expedite_regs;
>   | [...]
>   | while (*regp)
> 
> ... because, in our case, REGP is NULL.
> 
> This patch fixes the problem for Windows targets based on Intel
> (x86 and x86_64).
> 
> gdb/gdbserver/ChangeLog:
> 
> 	* win32-i386-low.c (i386_arch_setup): set tdesc->expedite_regs.
> ---
>  gdb/gdbserver/win32-i386-low.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/gdb/gdbserver/win32-i386-low.c b/gdb/gdbserver/win32-i386-low.c
> index a242f72..fdb95ce 100644
> --- a/gdb/gdbserver/win32-i386-low.c
> +++ b/gdb/gdbserver/win32-i386-low.c
> @@ -442,6 +442,16 @@ i386_arch_setup (void)
>  
>    init_target_desc (tdesc);
>  
> +#ifndef IN_PROCESS_AGENT
> +#ifdef __x86_64__
> +  static const char *expedite_regs_amd64[] = { "rbp", "rsp", "rip", NULL };
> +  tdesc->expedite_regs = expedite_regs_amd64;
> +#else /* __x86_64__ */
> +  static const char *expedite_regs_i386[] = { "ebp", "esp", "eip", NULL };
> +  tdesc->expedite_regs = expedite_regs_i386;
> +#endif /* __x86_64__ */
> +#endif

Won't all x86 ports have the same problem?  I.e., don't
nto-x86-low.c:nto_x86_arch_setup and
lynx-i386-low.c:lynx_i386_arch_setup need the same treatment?
Should we put those arrays in some shared i386 file?

Thanks,
Pedro Alves