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From: Andrew Burgess <aburgess@redhat.com>
To: Pedro Alves <pedro@palves.net>, gdb-patches@sourceware.org
Subject: Re: [PATCH 16/31] Move deleting thread on TARGET_WAITKIND_THREAD_EXITED to core
Date: Thu, 08 Jun 2023 13:27:27 +0100	[thread overview]
Message-ID: <87ttviyw9c.fsf@redhat.com> (raw)
In-Reply-To: <20221212203101.1034916-17-pedro@palves.net>

Pedro Alves <pedro@palves.net> writes:

> Currently, infrun assumes that when TARGET_WAITKIND_THREAD_EXITED is
> reported, the corresponding GDB thread has already been removed from
> the GDB thread list.
>
> Later in the series, that will no longer work, as infrun will need to
> refer to the thread's thread_info when it processes
> TARGET_WAITKIND_THREAD_EXITED.
>
> As preparation, this patch makes deleting the GDB thread
> responsibility of infrun, instead of the target.

LGTM.

Reviewed-By: Andrew Burgess <aburgess@redhat.com>

Thanks,
Andrew

>
> Change-Id: I013d87f61ffc9aaca49f0d6ce2a43e3ea69274de
> ---
>  gdb/infrun.c     | 31 ++++++++++++++++++++++++++-----
>  gdb/linux-nat.c  | 22 +++++++++++++++-------
>  gdb/netbsd-nat.c |  1 -
>  3 files changed, 41 insertions(+), 13 deletions(-)
>
> diff --git a/gdb/infrun.c b/gdb/infrun.c
> index c100bc70034..6fdffb31884 100644
> --- a/gdb/infrun.c
> +++ b/gdb/infrun.c
> @@ -4238,7 +4238,12 @@ reinstall_readline_callback_handler_cleanup ()
>  }
>  
>  /* Clean up the FSMs of threads that are now stopped.  In non-stop,
> -   that's just the event thread.  In all-stop, that's all threads.  */
> +   that's just the event thread.  In all-stop, that's all threads.  In
> +   all-stop, threads that had a pending exit no longer have a reason
> +   to be around, as their FSMs/commands are canceled, so we delete
> +   them.  This avoids "info threads" listing such threads as if they
> +   were alive (and failing to read their registers), the user being to
> +   select and resume them (and that failing), etc.  */
>  
>  static void
>  clean_up_just_stopped_threads_fsms (struct execution_control_state *ecs)
> @@ -4256,15 +4261,28 @@ clean_up_just_stopped_threads_fsms (struct execution_control_state *ecs)
>      {
>        scoped_restore_current_thread restore_thread;
>  
> -      for (thread_info *thr : all_non_exited_threads ())
> +      for (thread_info *thr : all_threads_safe ())
>  	{
> -	  if (thr->thread_fsm () == nullptr)
> +	  if (thr->state == THREAD_EXITED)
>  	    continue;
> +
>  	  if (thr == ecs->event_thread)
>  	    continue;
>  
> -	  switch_to_thread (thr);
> -	  thr->thread_fsm ()->clean_up (thr);
> +	  if (thr->thread_fsm () != nullptr)
> +	    {
> +	      switch_to_thread (thr);
> +	      thr->thread_fsm ()->clean_up (thr);
> +	    }
> +
> +	  /* As we are cancelling the command/FSM of this thread,
> +	     whatever was the reason we needed to report a thread
> +	     exited event to the user, that reason is gone.  Delete
> +	     the thread, so that the user doesn't see it in the thread
> +	     list, the next proceed doesn't try to resume it, etc.  */
> +	  if (thr->has_pending_waitstatus ()
> +	      && thr->pending_waitstatus ().kind () == TARGET_WAITKIND_THREAD_EXITED)
> +	    delete_thread (thr);
>  	}
>      }
>  }
> @@ -5537,6 +5555,9 @@ handle_inferior_event (struct execution_control_state *ecs)
>  
>    if (ecs->ws.kind () == TARGET_WAITKIND_THREAD_EXITED)
>      {
> +      ecs->event_thread = find_thread_ptid (ecs->target, ecs->ptid);
> +      gdb_assert (ecs->event_thread != nullptr);
> +      delete_thread (ecs->event_thread);
>        prepare_to_wait (ecs);
>        return;
>      }
> diff --git a/gdb/linux-nat.c b/gdb/linux-nat.c
> index 5fadc82deb0..b576ce60b75 100644
> --- a/gdb/linux-nat.c
> +++ b/gdb/linux-nat.c
> @@ -898,10 +898,11 @@ linux_nat_switch_fork (ptid_t new_ptid)
>    registers_changed ();
>  }
>  
> -/* Handle the exit of a single thread LP.  */
> +/* Handle the exit of a single thread LP.  If DEL_THREAD is true,
> +   delete the thread_info associated to LP, if it exists.  */
>  
>  static void
> -exit_lwp (struct lwp_info *lp)
> +exit_lwp (struct lwp_info *lp, bool del_thread = true)
>  {
>    struct thread_info *th = find_thread_ptid (linux_target, lp->ptid);
>  
> @@ -911,7 +912,8 @@ exit_lwp (struct lwp_info *lp)
>  	gdb_printf (_("[%s exited]\n"),
>  		    target_pid_to_str (lp->ptid).c_str ());
>  
> -      delete_thread (th);
> +      if (del_thread)
> +	delete_thread (th);
>      }
>  
>    delete_lwp (lp->ptid);
> @@ -3135,11 +3137,17 @@ filter_exit_event (struct lwp_info *event_child,
>    if (!is_leader (event_child))
>      {
>        if (report_thread_events)
> -	ourstatus->set_thread_exited (0);
> +	{
> +	  ourstatus->set_thread_exited (0);
> +	  /* Delete lwp, but not thread_info, infrun will need it to
> +	     process the event.  */
> +	  exit_lwp (event_child, false);
> +	}
>        else
> -	ourstatus->set_ignore ();
> -
> -      exit_lwp (event_child);
> +	{
> +	  ourstatus->set_ignore ();
> +	  exit_lwp (event_child);
> +	}
>      }
>  
>    return ptid;
> diff --git a/gdb/netbsd-nat.c b/gdb/netbsd-nat.c
> index bbadd865823..aa16a6cc5bd 100644
> --- a/gdb/netbsd-nat.c
> +++ b/gdb/netbsd-nat.c
> @@ -629,7 +629,6 @@ nbsd_nat_target::wait (ptid_t ptid, struct target_waitstatus *ourstatus,
>  	  if (print_thread_events)
>  	    gdb_printf (_("[%s exited]\n"),
>  			target_pid_to_str (wptid).c_str ());
> -	  delete_thread (thr);
>  	}
>  
>        /* The GDB core expects that the rest of the threads are running.  */
> -- 
> 2.36.0


  reply	other threads:[~2023-06-08 12:27 UTC|newest]

Thread overview: 100+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-12-12 20:30 [PATCH 00/31] Step over thread clone and thread exit Pedro Alves
2022-12-12 20:30 ` [PATCH 01/31] displaced step: pass down target_waitstatus instead of gdb_signal Pedro Alves
2023-02-03 10:44   ` Andrew Burgess
2023-03-10 17:15     ` Pedro Alves
2023-03-16 16:07       ` Andrew Burgess
2023-03-22 21:29         ` Andrew Burgess
2023-03-23 15:15           ` Pedro Alves
2023-03-27 12:40             ` Andrew Burgess
2023-03-27 16:21               ` Pedro Alves
2022-12-12 20:30 ` [PATCH 02/31] linux-nat: introduce pending_status_str Pedro Alves
2023-02-03 12:00   ` Andrew Burgess
2023-03-10 17:15     ` Pedro Alves
2023-03-16 16:19       ` Andrew Burgess
2023-03-27 18:05         ` Pedro Alves
2022-12-12 20:30 ` [PATCH 03/31] gdb/linux: Delete all other LWPs immediately on ptrace exec event Pedro Alves
2023-03-21 14:50   ` Andrew Burgess
2023-04-04 13:57     ` Pedro Alves
2023-04-14 19:29       ` Pedro Alves
2023-05-26 15:04         ` Andrew Burgess
2023-11-13 14:04           ` Pedro Alves
2023-05-26 14:45       ` Andrew Burgess
2022-12-12 20:30 ` [PATCH 04/31] Step over clone syscall w/ breakpoint, TARGET_WAITKIND_THREAD_CLONED Pedro Alves
2023-02-04 15:38   ` Andrew Burgess
2023-03-10 17:16     ` Pedro Alves
2023-03-21 16:06       ` Andrew Burgess
2023-11-13 14:05         ` Pedro Alves
2022-12-12 20:30 ` [PATCH 05/31] Support clone events in the remote protocol Pedro Alves
2023-03-22 15:46   ` Andrew Burgess
2023-11-13 14:05     ` Pedro Alves
2022-12-12 20:30 ` [PATCH 06/31] Avoid duplicate QThreadEvents packets Pedro Alves
2023-05-26 15:53   ` Andrew Burgess
2022-12-12 20:30 ` [PATCH 07/31] enum_flags to_string Pedro Alves
2023-01-30 20:07   ` Simon Marchi
2022-12-12 20:30 ` [PATCH 08/31] Thread options & clone events (core + remote) Pedro Alves
2023-01-31 12:25   ` Lancelot SIX
2023-03-10 19:16     ` Pedro Alves
2023-06-06 13:29       ` Andrew Burgess
2023-11-13 14:07         ` Pedro Alves
2022-12-12 20:30 ` [PATCH 09/31] Thread options & clone events (native Linux) Pedro Alves
2023-06-06 13:43   ` Andrew Burgess
2022-12-12 20:30 ` [PATCH 10/31] Thread options & clone events (Linux GDBserver) Pedro Alves
2023-06-06 14:12   ` Andrew Burgess
2023-11-13 14:07     ` Pedro Alves
2022-12-12 20:30 ` [PATCH 11/31] gdbserver: Hide and don't detach pending clone children Pedro Alves
2023-06-07 16:10   ` Andrew Burgess
2023-11-13 14:08     ` Pedro Alves
2022-12-12 20:30 ` [PATCH 12/31] Remove gdb/19675 kfails (displaced stepping + clone) Pedro Alves
2023-06-07 17:08   ` Andrew Burgess
2022-12-12 20:30 ` [PATCH 13/31] Add test for stepping over clone syscall Pedro Alves
2023-06-07 17:42   ` Andrew Burgess
2023-11-13 14:09     ` Pedro Alves
2022-12-12 20:30 ` [PATCH 14/31] all-stop/synchronous RSP support thread-exit events Pedro Alves
2023-06-07 17:52   ` Andrew Burgess
2023-11-13 14:11     ` Pedro Alves
2023-12-15 18:15       ` Pedro Alves
2022-12-12 20:30 ` [PATCH 15/31] gdbserver/linux-low.cc: Ignore event_ptid if TARGET_WAITKIND_IGNORE Pedro Alves
2022-12-12 20:30 ` [PATCH 16/31] Move deleting thread on TARGET_WAITKIND_THREAD_EXITED to core Pedro Alves
2023-06-08 12:27   ` Andrew Burgess [this message]
2022-12-12 20:30 ` [PATCH 17/31] Introduce GDB_THREAD_OPTION_EXIT thread option, fix step-over-thread-exit Pedro Alves
2023-06-08 13:17   ` Andrew Burgess
2022-12-12 20:30 ` [PATCH 18/31] Implement GDB_THREAD_OPTION_EXIT support for Linux GDBserver Pedro Alves
2023-06-08 14:14   ` Andrew Burgess
2022-12-12 20:30 ` [PATCH 19/31] Implement GDB_THREAD_OPTION_EXIT support for native Linux Pedro Alves
2023-06-08 14:17   ` Andrew Burgess
2022-12-12 20:30 ` [PATCH 20/31] gdb: clear step over information on thread exit (PR gdb/27338) Pedro Alves
2023-06-08 15:29   ` Andrew Burgess
2022-12-12 20:30 ` [PATCH 21/31] stop_all_threads: (re-)enable async before waiting for stops Pedro Alves
2023-06-08 15:49   ` Andrew Burgess
2023-11-13 14:12     ` Pedro Alves
2022-12-12 20:30 ` [PATCH 22/31] gdbserver: Queue no-resumed event after thread exit Pedro Alves
2023-06-08 18:16   ` Andrew Burgess
2023-11-13 14:12     ` Pedro Alves
2022-12-12 20:30 ` [PATCH 23/31] Don't resume new threads if scheduler-locking is in effect Pedro Alves
2023-06-08 18:24   ` Andrew Burgess
2023-11-13 14:12     ` Pedro Alves
2022-12-12 20:30 ` [PATCH 24/31] Report thread exit event for leader if reporting thread exit events Pedro Alves
2023-06-09 13:11   ` Andrew Burgess
2022-12-12 20:30 ` [PATCH 25/31] Ignore failure to read PC when resuming Pedro Alves
2023-06-10 10:33   ` Andrew Burgess
2023-11-13 14:13     ` Pedro Alves
2022-12-12 20:30 ` [PATCH 26/31] gdb/testsuite/lib/my-syscalls.S: Refactor new SYSCALL macro Pedro Alves
2023-06-10 10:33   ` Andrew Burgess
2022-12-12 20:30 ` [PATCH 27/31] Testcases for stepping over thread exit syscall (PR gdb/27338) Pedro Alves
2023-06-12  9:53   ` Andrew Burgess
2022-12-12 20:30 ` [PATCH 28/31] Document remote clone events, and QThreadOptions packet Pedro Alves
2023-06-05 15:53   ` Andrew Burgess
2023-11-13 14:13     ` Pedro Alves
2023-06-12 12:06   ` Andrew Burgess
2023-11-13 14:15     ` Pedro Alves
2022-12-12 20:30 ` [PATCH 29/31] inferior::clear_thread_list always silent Pedro Alves
2023-06-12 12:20   ` Andrew Burgess
2022-12-12 20:31 ` [PATCH 30/31] Centralize "[Thread ...exited]" notifications Pedro Alves
2023-02-04 16:05   ` Andrew Burgess
2023-03-10 17:21     ` Pedro Alves
2023-02-16 15:40   ` Andrew Burgess
2023-06-12 12:23     ` Andrew Burgess
2022-12-12 20:31 ` [PATCH 31/31] Cancel execution command on thread exit, when stepping, nexting, etc Pedro Alves
2023-06-12 13:12   ` Andrew Burgess
2023-01-24 19:47 ` [PATCH v3 00/31] Step over thread clone and thread exit Pedro Alves
2023-11-13 14:24 ` [PATCH " Pedro Alves

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