Re: [PATCH] [MIPS] Use lwpid from lwp_info instead of inferior_ptid

[Simon Marchi <simon.marchi@polymtl.ca>]

On 2017-04-27 10:23, Yao Qi wrote:
> RAJESH reported that GDB gets "Couldn't write debug register: No such
> process." on mips64 when GDB attaches to a multi threaded application.
> 
> Looks GDB nows PTRACE_GET_WATCH_REGS for inferior_ptid but
> PTRACE_SET_WATCH_REGS for lwp->ptid, they may be different.
> 
> gdb:
> 
> 2017-04-27  Yao Qi  <yao.qi@linaro.org>
> 
> 	* mips-linux-nat.c (mips_linux_new_thread): Get lwpid from
> 	lwp_info instead of getting from inferior_ptid.
> ---
>  gdb/mips-linux-nat.c | 5 ++---
>  1 file changed, 2 insertions(+), 3 deletions(-)
> 
> diff --git a/gdb/mips-linux-nat.c b/gdb/mips-linux-nat.c
> index 9596b49..c5c18fd 100644
> --- a/gdb/mips-linux-nat.c
> +++ b/gdb/mips-linux-nat.c
> @@ -624,14 +624,13 @@ write_watchpoint_regs (void)
>  static void
>  mips_linux_new_thread (struct lwp_info *lp)
>  {
> -  int tid;
> +  long tid = ptid_get_lwp (lp->ptid);

You can replace this with "lp->ptid.lwp ()".

Otherwise, LGTM.

> 
> -  if (!mips_linux_read_watch_registers (ptid_get_lwp (inferior_ptid),
> +  if (!mips_linux_read_watch_registers (tid,
>  					&watch_readback,
>  					&watch_readback_valid, 0))
>      return;
> 
> -  tid = ptid_get_lwp (lp->ptid);
>    if (ptrace (PTRACE_SET_WATCH_REGS, tid, &watch_mirror, NULL) == -1)
>      perror_with_name (_("Couldn't write debug register"));
>  }