From: Andrew Burgess <aburgess@redhat.com>
To: Pedro Alves <pedro@palves.net>, gdb-patches@sourceware.org
Subject: Re: [PATCH 22/31] gdbserver: Queue no-resumed event after thread exit
Date: Thu, 08 Jun 2023 19:16:38 +0100 [thread overview]
Message-ID: <877csdzunt.fsf@redhat.com> (raw)
In-Reply-To: <20221212203101.1034916-23-pedro@palves.net>
Pedro Alves <pedro@palves.net> writes:
> Normally, if the last thread resumed thread on the target exits, the
"thread resumed thread" .... I think there's an extra 'thread' in there.
Otherwise, LGTM.
Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Thanks,
Andrew
> server sends a no-resumed event to GDB. If however, GDB enables the
> GDB_THREAD_OPTION_EXIT option on a thread, and, that thread exits, the
> server sends a thread exit event for that thread instead.
>
> In all-stop RSP mode, since events can only be forwarded to GDB one at
> a time, and the whole target stops whenever an event is reported, GDB
> resumes the target again after getting a THREAD_EXITED event, and then
> the server finally reports back a no-resumed event if/when
> appropriate.
>
> For non-stop RSP though, events are asynchronous, and if the server
> sends a thread-exit event for the last resumed thread, the no-resumed
> event is never sent. This patch makes sure that in non-stop mode, the
> server queues a no-resumed event after the thread-exit event if it was
> the last resumed thread that exited.
>
> Without this, we'd see failures in step-over-thread-exit testcases
> added later in the series, like so:
>
> continue
> Continuing.
> - No unwaited-for children left.
> - (gdb) PASS: gdb.threads/step-over-thread-exit.exp: displaced-stepping=off: non-stop=on: target-non-stop=on: schedlock=off: ns_stop_all=1: continue stops when thread exits
> + FAIL: gdb.threads/step-over-thread-exit.exp: displaced-stepping=off: non-stop=on: target-non-stop=on: schedlock=off: ns_stop_all=1: continue stops when thread exits (timeout)
>
> (and other similar ones)
>
> Change-Id: I927d78b30f88236dbd5634b051a716f72420e7c7
> ---
> gdbserver/linux-low.cc | 47 +++++++++++++++++++++++++-----------------
> gdbserver/linux-low.h | 2 ++
> gdbserver/server.cc | 12 ++++++++++-
> gdbserver/target.cc | 6 ++++++
> gdbserver/target.h | 6 ++++++
> 5 files changed, 53 insertions(+), 20 deletions(-)
>
> diff --git a/gdbserver/linux-low.cc b/gdbserver/linux-low.cc
> index ebc3bf34127..bf6dc1d995a 100644
> --- a/gdbserver/linux-low.cc
> +++ b/gdbserver/linux-low.cc
> @@ -2963,7 +2963,6 @@ linux_process_target::wait_1 (ptid_t ptid, target_waitstatus *ourstatus,
> int report_to_gdb;
> int trace_event;
> int in_step_range;
> - int any_resumed;
>
> threads_debug_printf ("[%s]", target_pid_to_str (ptid).c_str ());
>
> @@ -2977,23 +2976,7 @@ linux_process_target::wait_1 (ptid_t ptid, target_waitstatus *ourstatus,
> in_step_range = 0;
> ourstatus->set_ignore ();
>
> - auto status_pending_p_any = [&] (thread_info *thread)
> - {
> - return status_pending_p_callback (thread, minus_one_ptid);
> - };
> -
> - auto not_stopped = [&] (thread_info *thread)
> - {
> - return not_stopped_callback (thread, minus_one_ptid);
> - };
> -
> - /* Find a resumed LWP, if any. */
> - if (find_thread (status_pending_p_any) != NULL)
> - any_resumed = 1;
> - else if (find_thread (not_stopped) != NULL)
> - any_resumed = 1;
> - else
> - any_resumed = 0;
> + bool was_any_resumed = any_resumed ();
>
> if (step_over_bkpt == null_ptid)
> pid = wait_for_event (ptid, &w, options);
> @@ -3004,7 +2987,7 @@ linux_process_target::wait_1 (ptid_t ptid, target_waitstatus *ourstatus,
> pid = wait_for_event (step_over_bkpt, &w, options & ~WNOHANG);
> }
>
> - if (pid == 0 || (pid == -1 && !any_resumed))
> + if (pid == 0 || (pid == -1 && !was_any_resumed))
> {
> gdb_assert (target_options & TARGET_WNOHANG);
>
> @@ -6166,6 +6149,32 @@ linux_process_target::thread_stopped (thread_info *thread)
> return get_thread_lwp (thread)->stopped;
> }
>
> +bool
> +linux_process_target::any_resumed ()
> +{
> + bool any_resumed;
> +
> + auto status_pending_p_any = [&] (thread_info *thread)
> + {
> + return status_pending_p_callback (thread, minus_one_ptid);
> + };
> +
> + auto not_stopped = [&] (thread_info *thread)
> + {
> + return not_stopped_callback (thread, minus_one_ptid);
> + };
> +
> + /* Find a resumed LWP, if any. */
> + if (find_thread (status_pending_p_any) != NULL)
> + any_resumed = 1;
> + else if (find_thread (not_stopped) != NULL)
> + any_resumed = 1;
> + else
> + any_resumed = 0;
> +
> + return any_resumed;
> +}
> +
> /* This exposes stop-all-threads functionality to other modules. */
>
> void
> diff --git a/gdbserver/linux-low.h b/gdbserver/linux-low.h
> index 1c1754d2b59..33a14e15173 100644
> --- a/gdbserver/linux-low.h
> +++ b/gdbserver/linux-low.h
> @@ -259,6 +259,8 @@ class linux_process_target : public process_stratum_target
>
> bool thread_stopped (thread_info *thread) override;
>
> + bool any_resumed () override;
> +
> void pause_all (bool freeze) override;
>
> void unpause_all (bool unfreeze) override;
> diff --git a/gdbserver/server.cc b/gdbserver/server.cc
> index 5099db1ee31..77b4b57466d 100644
> --- a/gdbserver/server.cc
> +++ b/gdbserver/server.cc
> @@ -4740,7 +4740,17 @@ handle_target_event (int err, gdb_client_data client_data)
> }
> }
> else
> - push_stop_notification (cs.last_ptid, cs.last_status);
> + {
> + push_stop_notification (cs.last_ptid, cs.last_status);
> +
> + if (cs.last_status.kind () == TARGET_WAITKIND_THREAD_EXITED
> + && !target_any_resumed ())
> + {
> + target_waitstatus ws;
> + ws.set_no_resumed ();
> + push_stop_notification (null_ptid, ws);
> + }
> + }
> }
>
> /* Be sure to not change the selected thread behind GDB's back.
> diff --git a/gdbserver/target.cc b/gdbserver/target.cc
> index 4584e9b3a8e..833e32a4830 100644
> --- a/gdbserver/target.cc
> +++ b/gdbserver/target.cc
> @@ -612,6 +612,12 @@ process_stratum_target::thread_stopped (thread_info *thread)
> gdb_assert_not_reached ("target op thread_stopped not supported");
> }
>
> +bool
> +process_stratum_target::any_resumed ()
> +{
> + return true;
> +}
> +
> bool
> process_stratum_target::supports_get_tib_address ()
> {
> diff --git a/gdbserver/target.h b/gdbserver/target.h
> index e2e818b130b..c3345fc67e8 100644
> --- a/gdbserver/target.h
> +++ b/gdbserver/target.h
> @@ -320,6 +320,9 @@ class process_stratum_target
> /* Return true if THREAD is known to be stopped now. */
> virtual bool thread_stopped (thread_info *thread);
>
> + /* Return true if any thread is known to be resumed. */
> + virtual bool any_resumed ();
> +
> /* Return true if the get_tib_address op is supported. */
> virtual bool supports_get_tib_address ();
>
> @@ -683,6 +686,9 @@ target_read_btrace_conf (struct btrace_target_info *tinfo,
> #define target_supports_software_single_step() \
> the_target->supports_software_single_step ()
>
> +#define target_any_resumed() \
> + the_target->any_resumed ()
> +
> ptid_t mywait (ptid_t ptid, struct target_waitstatus *ourstatus,
> target_wait_flags options, int connected_wait);
>
> --
> 2.36.0
next prev parent reply other threads:[~2023-06-08 18:16 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 " 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
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 [this message]
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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