Re: [PATCH] PR threads/20743: Don't attempt to suspend or resume exited threads.

[Luis Machado <lgustavo@codesourcery.com>]

On 12/23/2016 03:28 PM, John Baldwin wrote:
> When resuming a native FreeBSD process, ignore exited threads when
> suspending/resuming individual threads prior to continuing the process.
>
> gdb/ChangeLog:
>
> 	PR threads/20743
> 	* fbsd-nat.c (resume_one_thread_cb): Ignore exited threads.
> 	(resume_all_threads_cb): Likewise.
> 	(fbsd_resume): Assert resuming thread has not exited.
> ---
>  gdb/ChangeLog  | 7 +++++++
>  gdb/fbsd-nat.c | 7 +++++++
>  2 files changed, 14 insertions(+)
>
> diff --git a/gdb/ChangeLog b/gdb/ChangeLog
> index db6e913..4fb3732 100644
> --- a/gdb/ChangeLog
> +++ b/gdb/ChangeLog
> @@ -1,3 +1,10 @@
> +2016-12-23  John Baldwin  <jhb@FreeBSD.org>
> +
> +	PR threads/20743
> +	* fbsd-nat.c (resume_one_thread_cb): Ignore exited threads.
> +	(resume_all_threads_cb): Likewise.
> +	(fbsd_resume): Assert resuming thread has not exited.
> +
>  2016-12-22  Doug Evans  <xdje42@gmail.com>
>
>  	* infrun.c (set_step_over_info): Add comment.
> diff --git a/gdb/fbsd-nat.c b/gdb/fbsd-nat.c
> index ade62f1..7cd08c6 100644
> --- a/gdb/fbsd-nat.c
> +++ b/gdb/fbsd-nat.c
> @@ -662,6 +662,9 @@ resume_one_thread_cb (struct thread_info *tp, void *data)
>    if (ptid_get_pid (tp->ptid) != ptid_get_pid (*ptid))
>      return 0;
>
> +  if (is_exited (tp->ptid))
> +    return 0;
> +		
>    if (ptid_get_lwp (tp->ptid) == ptid_get_lwp (*ptid))
>      request = PT_RESUME;
>    else
> @@ -680,6 +683,9 @@ resume_all_threads_cb (struct thread_info *tp, void *data)
>    if (!ptid_match (tp->ptid, *filter))
>      return 0;
>
> +  if (is_exited (tp->ptid))
> +    return 0;
> +		
>    if (ptrace (PT_RESUME, ptid_get_lwp (tp->ptid), NULL, 0) == -1)
>      perror_with_name (("ptrace"));
>    return 0;
> @@ -711,6 +717,7 @@ fbsd_resume (struct target_ops *ops,
>    if (ptid_lwp_p (ptid))
>      {
>        /* If ptid is a specific LWP, suspend all other LWPs in the process.  */
> +      gdb_assert (!is_exited (ptid));

If we're asserting on this (since supposedly it shouldn't happen), do we 
need to check for is_exited on the two functions above?

Also, is there a reason why we're not detecting a thread that has 
exited? Aren't all threads stopped at this point (for all-stop mode at 
least)?

>        iterate_over_threads (resume_one_thread_cb, &ptid);
>      }
>    else
>