Re: [PATCH 3/3] [fix] Skip over WIFSTOPPED wait4 status

[Simon Marchi via Gdb-patches <gdb-patches@sourceware.org>]

On 2021-04-08 3:14 p.m., Dominique Quatravaux via Gdb-patches wrote:
> On modern Darwin's, there appears to be a new circumstance in which a
> MACH_NOTIFY_DEAD_NAME message can be received, and which was not
> previously accounted for: to signal the WIFSTOPPED condition in the
> debuggee. In that case the debuggee is not dead yet (and in fact,
> counting it as dead would cause a zombie leak - A process in such a
> state reparents to PID 1, but cannot be killed).
> 
> - Read and ignore such messages (counting on the next exception
> message to let us know of the inferior's new state again)
> - Refactor logging so as to clearly distinguish between the three
> MACH_NOTIFY_DEAD_NAME cases (WIFEXITED, WIFSTOPPED, signal)
> ---
>  gdb/darwin-nat.c | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/gdb/darwin-nat.c b/gdb/darwin-nat.c
> index 9c6423ceb02..cbe36eba626 100644
> --- a/gdb/darwin-nat.c
> +++ b/gdb/darwin-nat.c
> @@ -1053,7 +1053,7 @@ darwin_nat_target::decode_message (mach_msg_header_t *hdr,
>      }
>    else if (hdr->msgh_id == 0x48)
>      {
> -      /* MACH_NOTIFY_DEAD_NAME: notification for exit.  */
> +      /* MACH_NOTIFY_DEAD_NAME: notification for exit *or* WIFSTOPPED.  */
>        int res;
>  
>        res = darwin_decode_notify_message (hdr, &inf);
> @@ -1096,16 +1096,23 @@ darwin_nat_target::decode_message (mach_msg_header_t *hdr,
>  		{
>  		  status->kind = TARGET_WAITKIND_EXITED;
>  		  status->value.integer = WEXITSTATUS (wstatus);
> +		  inferior_debug (4, _("darwin_wait: pid=%d exit, status=0x%x\n"),
> +				  res_pid, wstatus);
> +		}
> +	      else if (WIFSTOPPED (wstatus))
> +		{
> +		  status->kind = TARGET_WAITKIND_IGNORE;
> +		  inferior_debug (4, _("darwin_wait: pid %d received WIFSTOPPED\n"), res_pid);
> +		  return minus_one_ptid;
>  		}
>  	      else
>  		{
>  		  status->kind = TARGET_WAITKIND_SIGNALLED;
>  		  status->value.sig = gdb_signal_from_host (WTERMSIG (wstatus));
> +		  inferior_debug (4, _("darwin_wait: pid=%d received signal %d\n"),
> +			      res_pid, status->value.sig);
>  		}
>  
> -	      inferior_debug (4, _("darwin_wait: pid=%d exit, status=0x%x\n"),
> -			      res_pid, wstatus);
> -
>  	      return ptid_t (inf->pid);
>  	    }
>  	  else
> 

Thanks, that LGTM.  Let's just way until your copyright assigment is complete.

Simon