From ef980d654ba22aad6b5b301179dd105f522b56a1 Mon Sep 17 00:00:00 2001 From: Pedro Alves Date: Fri, 22 Apr 2022 21:03:07 +0100 Subject: [PATCH] gdbserver: Queue no-resumed event after thread exit Normally, if the last resumed thread on the target exits, the 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) Reviewed-By: Andrew Burgess 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 b4a1191b5b4..44d0fe38030 100644 --- a/gdbserver/linux-low.cc +++ b/gdbserver/linux-low.cc @@ -2972,7 +2972,6 @@ 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 ()); @@ -2986,23 +2985,7 @@ 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); @@ -3013,7 +2996,7 @@ 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); @@ -6177,6 +6160,32 @@ 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 3597e33289c..d46ea5aa3ec 100644 --- a/gdbserver/linux-low.h +++ b/gdbserver/linux-low.h @@ -259,6 +259,8 @@ public: 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 4a312da40bc..a8e23561dcb 100644 --- a/gdbserver/server.cc +++ b/gdbserver/server.cc @@ -4731,7 +4731,17 @@ 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 dbb4e2d9024..81edff41268 100644 --- a/gdbserver/target.cc +++ b/gdbserver/target.cc @@ -614,6 +614,12 @@ 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 0f1fd5906fb..28d134e7915 100644 --- a/gdbserver/target.h +++ b/gdbserver/target.h @@ -319,6 +319,9 @@ public: /* 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); -- 2.30.2