[PATCH v2 0/6] fix PR gdb/19340

[PATCH v2 0/6] fix PR gdb/19340

[Markus Metzger]

Fix PR gdb/19340 by stopping replaying the current thread before disabling
recording.

While writing the test for this, I wondered whether it would also work if
there was more than one process and if some were recording while others
were replaying.

It turned out that recording one process while some other process is
replaying doesn't work.  You first have to stop replaying everything
before you can continue recording.  Since btrace is per inferior, this
seems like an unnecessary restriction.

The first patch fixes gdb/pr19340; the rest makes recording work together
with replaying on inferior level.

The most prominent change is probably that do_target_wait() no longer
silently switches inferiors.  This infrun change requires global
maintainer approval.

Changes to v1:
  - fixed a fail in a newly added test
  - fixed fails in patch 5, which also caused the patch to get renamed

Markus Metzger (6):
  gdb, btrace: fix pr19340
  gdb, btrace: simplify gdb.btrace/multi-inferior.exp
  gdb, btrace: remove record_btrace_target::supports_*()
  gdb, btrace: set wait status to ignore if nothing is moving
  gdb, infrun: fix silent inferior switch in do_target_wait()
  gdb, btrace, infrun: per-inferior run-control

 gdb/infrun.c                                | 63 ++++++++++++++---
 gdb/linux-nat.c                             | 17 +++--
 gdb/record-btrace.c                         | 78 +++++++--------------
 gdb/remote.c                                | 22 ++++--
 gdb/testsuite/gdb.btrace/multi-inferior.c   | 10 ++-
 gdb/testsuite/gdb.btrace/multi-inferior.exp | 33 ++++-----
 gdb/testsuite/gdb.btrace/step.exp           | 22 ++++--
 7 files changed, 150 insertions(+), 95 deletions(-)

-- 
2.34.1

Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928

[PATCH v2 1/6] gdb, btrace: fix pr19340

[Markus Metzger]

GDB fails with an assertion when stopping recording on a replaying thread
and then resuming that thread.  Stopping recording left the thread
replaying but the record target is gone.

Stop replaying all threads in the selected inferior before stopping recording.

If the selected thread had been replaying, print the (potentially updated)
location.

I had to change the stepping test slightly to account for different
compilers generating slightly different debug information, so when
stepping the 'return 0' after 'record stop' I would end up in a different
location depending on which compiler I used.  The test still covers all
stepping commands.

Fixes PR gdb/19340.
---
 gdb/record-btrace.c               | 17 +++++++++++++++++
 gdb/testsuite/gdb.btrace/step.exp | 22 +++++++++++++++-------
 2 files changed, 32 insertions(+), 7 deletions(-)

diff --git a/gdb/record-btrace.c b/gdb/record-btrace.c
index 0ef1dfbe652..1d946f9d3f2 100644
--- a/gdb/record-btrace.c
+++ b/gdb/record-btrace.c
@@ -414,11 +414,28 @@ record_btrace_target::stop_recording ()
 {
   DEBUG ("stop recording");
 
+  /* Remember the selected thread if it exists and is replaying.  */
+  thread_info *curr = nullptr;
+  if (inferior_ptid.lwp_p ())
+    {
+      curr = inferior_thread ();
+      if (!btrace_is_replaying (curr))
+	curr = nullptr;
+    }
+
+  record_stop_replaying ();
   record_btrace_auto_disable ();
 
   for (thread_info *tp : current_inferior ()->non_exited_threads ())
     if (tp->btrace.target != NULL)
       btrace_disable (tp);
+
+  /* Print the updated location in case we had stopped a replaying thread.  */
+  if (curr != nullptr)
+    {
+      curr->set_stop_pc (regcache_read_pc (get_thread_regcache (curr)));
+      print_stack_frame (get_selected_frame (), 1, SRC_AND_LOC, 1);
+    }
 }
 
 /* The disconnect method of target record-btrace.  */
diff --git a/gdb/testsuite/gdb.btrace/step.exp b/gdb/testsuite/gdb.btrace/step.exp
index 0adc18bd924..ed6d2140bdd 100644
--- a/gdb/testsuite/gdb.btrace/step.exp
+++ b/gdb/testsuite/gdb.btrace/step.exp
@@ -31,18 +31,26 @@ if ![runto_main] {
 # trace the call to the test function
 with_test_prefix "record" {
     gdb_test_no_output "record btrace"
-    gdb_test "next"
+    gdb_test "step"
+    gdb_test "next 2"
 }
 
 # let's step around a bit
 with_test_prefix "replay" {
-    gdb_test "reverse-next" ".*main\.2.*" "reverse-next.1"
+    gdb_test "reverse-finish" ".*main\.2.*" "reverse-finish.1"
     gdb_test "step" ".*fun4\.2.*" "step.1"
     gdb_test "next" ".*fun4\.3.*" "next.1"
     gdb_test "step" ".*fun2\.2.*" "step.2"
-    gdb_test "finish" ".*fun4\.4.*" "finish.1"
-    gdb_test "reverse-step" ".*fun2\.3.*" "reverse-step.1"
-    gdb_test "reverse-finish" ".*fun4\.3.*" "reverse-finish.1"
-    gdb_test "reverse-next" ".*fun4\.2.*" "reverse-next.2"
-    gdb_test "reverse-finish" ".*main\.2.*" "reverse-finish.2"
+    gdb_test "reverse-finish" ".*fun4\.3.*" "reverse-finish.2"
+    gdb_test "reverse-step" ".*fun1\.2.*" "reverse-step.1"
+    gdb_test "finish" ".*fun4\.3.*" "finish.1"
+    gdb_test "reverse-next" ".*fun4\.2.*" "reverse-next.1"
+    gdb_test "reverse-finish" ".*main\.2.*" "reverse-finish.3"
+}
+
+# stop recording and try to step live (pr19340)
+with_test_prefix "live" {
+    gdb_test "record stop" "fun4\.4.*Process record is stopped.*"
+    gdb_test "reverse-next" "Target .* does not support this command.*"
+    gdb_test "step" ".*fun3\.2.*"
 }
-- 
2.34.1

Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928

[PATCH v2 2/6] gdb, btrace: simplify gdb.btrace/multi-inferior.exp

[Markus Metzger]

We don't really need three inferiors to test multi-inferior recording.
We don't really need to start recording on the second inferior first.
We don't really need to check info record before starting recording.
If we were recording, there would be output, causing a fail.

This just complicates the test when there is something to debug.
---
 gdb/testsuite/gdb.btrace/multi-inferior.exp | 24 +++------------------
 1 file changed, 3 insertions(+), 21 deletions(-)

diff --git a/gdb/testsuite/gdb.btrace/multi-inferior.exp b/gdb/testsuite/gdb.btrace/multi-inferior.exp
index 6996b182e65..174d38364a4 100644
--- a/gdb/testsuite/gdb.btrace/multi-inferior.exp
+++ b/gdb/testsuite/gdb.btrace/multi-inferior.exp
@@ -37,6 +37,8 @@ with_test_prefix "inferior 1" {
     if ![runto_main] {
 	return -1
     }
+
+    gdb_test_no_output "record btrace"
 }
 
 with_test_prefix "inferior 2" {
@@ -48,25 +50,5 @@ with_test_prefix "inferior 2" {
 	return -1
     }
 
-    gdb_test_no_output "record btrace" "record btrace"
-}
-
-with_test_prefix "inferior 1" {
-    gdb_test "inferior 1" "Switching to inferior 1.*"
-
-    gdb_test "info record" "No recording is currently active\\."
-    gdb_test_no_output "record btrace" "record btrace"
-}
-
-with_test_prefix "inferior 3" {
-    gdb_test "add-inferior -exec ${host_binfile}" "Added inferior 3.*" \
-	"add third inferior"
-    gdb_test "inferior 3" "Switching to inferior 3.*"
-
-    if ![runto_main] {
-	return -1
-    }
-
-    gdb_test "info record" "No recording is currently active\\."
-    gdb_test_no_output "record btrace" "record btrace"
+    gdb_test_no_output "record btrace"
 }
-- 
2.34.1

Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928

[PATCH v2 3/6] gdb, btrace: remove record_btrace_target::supports_*()

[Markus Metzger]

Let's not introduce support for breakpoint types the target beneath does
not support, even though we could while replaying.

Otherwise, users may set breakpoints during replay that then couldn't be
inserted into the target when switching back to recording.
---
 gdb/record-btrace.c | 27 ---------------------------
 1 file changed, 27 deletions(-)

diff --git a/gdb/record-btrace.c b/gdb/record-btrace.c
index 1d946f9d3f2..66f283b8680 100644
--- a/gdb/record-btrace.c
+++ b/gdb/record-btrace.c
@@ -130,10 +130,7 @@ class record_btrace_target final : public target_ops
   bool can_execute_reverse () override;
 
   bool stopped_by_sw_breakpoint () override;
-  bool supports_stopped_by_sw_breakpoint () override;
-
   bool stopped_by_hw_breakpoint () override;
-  bool supports_stopped_by_hw_breakpoint () override;
 
   enum exec_direction_kind execution_direction () override;
   void prepare_to_generate_core () override;
@@ -2706,18 +2703,6 @@ record_btrace_target::stopped_by_sw_breakpoint ()
   return this->beneath ()->stopped_by_sw_breakpoint ();
 }
 
-/* The supports_stopped_by_sw_breakpoint method of target
-   record-btrace.  */
-
-bool
-record_btrace_target::supports_stopped_by_sw_breakpoint ()
-{
-  if (record_is_replaying (minus_one_ptid))
-    return true;
-
-  return this->beneath ()->supports_stopped_by_sw_breakpoint ();
-}
-
 /* The stopped_by_sw_breakpoint method of target record-btrace.  */
 
 bool
@@ -2733,18 +2718,6 @@ record_btrace_target::stopped_by_hw_breakpoint ()
   return this->beneath ()->stopped_by_hw_breakpoint ();
 }
 
-/* The supports_stopped_by_hw_breakpoint method of target
-   record-btrace.  */
-
-bool
-record_btrace_target::supports_stopped_by_hw_breakpoint ()
-{
-  if (record_is_replaying (minus_one_ptid))
-    return true;
-
-  return this->beneath ()->supports_stopped_by_hw_breakpoint ();
-}
-
 /* The update_thread_list method of target record-btrace.  */
 
 void
-- 
2.34.1

Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928

[PATCH v2 4/6] gdb, btrace: set wait status to ignore if nothing is moving

[Markus Metzger]

When record_btrace::wait() is called and no threads are moving, we set the
wait status to no_resumed.  Change that to ignore.

This helps with enabling per-inferior run-control for the record btrace
target as it avoids breaking out of do_target_wait() too early with
no_resumed when there would have been an event on another thread.
---
 gdb/record-btrace.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/gdb/record-btrace.c b/gdb/record-btrace.c
index 66f283b8680..53ed481eb4d 100644
--- a/gdb/record-btrace.c
+++ b/gdb/record-btrace.c
@@ -2279,14 +2279,14 @@ btrace_step_spurious (void)
   return status;
 }
 
-/* Return a target_waitstatus indicating that the thread was not resumed.  */
+/* Return a target_waitstatus indicating that nothing is moving.  */
 
 static struct target_waitstatus
-btrace_step_no_resumed (void)
+btrace_step_no_moving_threads (void)
 {
   struct target_waitstatus status;
 
-  status.set_no_resumed ();
+  status.set_ignore ();
 
   return status;
 }
@@ -2555,7 +2555,7 @@ record_btrace_target::wait (ptid_t ptid, struct target_waitstatus *status,
 
   if (moving.empty ())
     {
-      *status = btrace_step_no_resumed ();
+      *status = btrace_step_no_moving_threads ();
 
       DEBUG ("wait ended by %s: %s", null_ptid.to_string ().c_str (),
 	     status->to_string ().c_str ());
-- 
2.34.1

Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928

[PATCH v2 5/6] gdb, infrun: fix silent inferior switch in do_target_wait()

[Markus Metzger]

In do_target_wait(), we iterate over inferiors and call
do_target_wait_1(), which eventually calls target_wait() per inferior.
Each time, we wait for minus_one_ptid.

In some cases, e.g. gdb.threads/detach-step-over.exp, we ask to wait for
one inferior, and get an event from a different inferior back without
noticing the inferior switch.

Wait for a single inferior, instead.  Since we iterate over all inferiors,
we still cover everything.

This exposes another bug with STOP_QUIETLY_NO_SIGSTOP handling.

After attaching, we interrupt all threads in the new inferior, then call
do_target_wait() to receive the stopped events.  This randomly selects an
inferior to start waiting for and iterates over all inferiors starting
from there.

The initial stop event for the main thread is already queued up, so we
wouldn't actually wait() if we had started with the new inferior.  Or if
we had waited for minus_one_ptid, which would then have silently switched
inferiors.

Since we no longer allow that, we may actually wait() for the new inferior
and find other events to report, out of which we randomly select one.

If we selected an event for another thread, e.g. one that had been
interrupted as part of non-stop attach, STOP_QUIETLY_NO_SIGSTOP would be
applied to that thread (unnecessarily), leaving the main thread with a
SIGSTOP event but last_resume_kind = 0 (resume_continue).

When the main thread is later selected, SIGSTOP is reported to the user.

Normally, linux-nat's wait() turns the SIGSTOP it uses for interrupting
threads into GDB_SIGNAL_0.  This is based on last_resume_kind, which is
set to 2 (resume_stop) when sending SIGSTOP to interrupt a thread.

We do this for all threads of the new inferior when interrupting them as
part of non-stop attach.  Except for the main thread, which we expect to
be reported before the first wait().

Set last_resume_kind to resume_stop for the main thread after attaching.
---
 gdb/infrun.c    | 46 +++++++++++++++++++++++++++++++++++++++++++---
 gdb/linux-nat.c | 17 ++++++++++++-----
 gdb/remote.c    | 22 +++++++++++++++++-----
 3 files changed, 72 insertions(+), 13 deletions(-)

diff --git a/gdb/infrun.c b/gdb/infrun.c
index a5030b16376..9ca0571065c 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -4198,7 +4198,23 @@ do_target_wait (ptid_t wait_ptid, execution_control_state *ecs,
 
   auto do_wait = [&] (inferior *inf)
   {
-    ecs->ptid = do_target_wait_1 (inf, wait_ptid, &ecs->ws, options);
+    ptid_t ptid { inf->pid };
+
+    /* Make sure we're not widening WAIT_PTID.  */
+    if (!ptid.matches (wait_ptid)
+	/* Targets that cannot async will be asked for a blocking wait.
+
+	   Blocking wait does not work inferior-by-inferior if the target
+	   provides more than one inferior.  Fall back to waiting for
+	   WAIT_PTID in that case.  */
+	|| !target_can_async_p () || ((options & TARGET_WNOHANG) == 0)
+	/* FIXME: I don't see why we should have inferiors with zero pid,
+	   which indicates that the respective ptid is not a process.
+	   They do exist, though, and we cannot wait for them.  */
+	|| !ptid.is_pid ())
+      ptid = wait_ptid;
+
+    ecs->ptid = do_target_wait_1 (inf, ptid, &ecs->ws, options);
     ecs->target = inf->process_target ();
     return (ecs->ws.kind () != TARGET_WAITKIND_IGNORE);
   };
@@ -4208,6 +4224,12 @@ do_target_wait (ptid_t wait_ptid, execution_control_state *ecs,
      reported the stop to the user, polling for events.  */
   scoped_restore_current_thread restore_thread;
 
+  /* The first TARGET_WAITKIND_NO_RESUMED execution state.
+
+     If we do not find a more interesting event, we will report that.  */
+  execution_control_state no_resumed {};
+  no_resumed.ptid = null_ptid;
+
   intrusive_list_iterator<inferior> start
     = inferior_list.iterator_to (*selected);
 
@@ -4218,7 +4240,13 @@ do_target_wait (ptid_t wait_ptid, execution_control_state *ecs,
       inferior *inf = &*it;
 
       if (inferior_matches (inf) && do_wait (inf))
-	return true;
+	{
+	  if (ecs->ws.kind () != TARGET_WAITKIND_NO_RESUMED)
+	    return true;
+
+	  if (no_resumed.ptid == null_ptid)
+	    no_resumed = *ecs;
+	}
     }
 
   for (intrusive_list_iterator<inferior> it = inferior_list.begin ();
@@ -4228,7 +4256,19 @@ do_target_wait (ptid_t wait_ptid, execution_control_state *ecs,
       inferior *inf = &*it;
 
       if (inferior_matches (inf) && do_wait (inf))
-	return true;
+	{
+	  if (ecs->ws.kind () != TARGET_WAITKIND_NO_RESUMED)
+	    return true;
+
+	  if (no_resumed.ptid == null_ptid)
+	    no_resumed = *ecs;
+	}
+    }
+
+  if (no_resumed.ptid != null_ptid)
+    {
+      *ecs = no_resumed;
+      return true;
     }
 
   ecs->ws.set_ignore ();
diff --git a/gdb/linux-nat.c b/gdb/linux-nat.c
index 2602e1f240d..06b39d67a72 100644
--- a/gdb/linux-nat.c
+++ b/gdb/linux-nat.c
@@ -1154,6 +1154,7 @@ linux_nat_target::attach (const char *args, int from_tty)
 
   /* Add the initial process as the first LWP to the list.  */
   lp = add_initial_lwp (ptid);
+  lp->last_resume_kind = resume_stop;
 
   status = linux_nat_post_attach_wait (lp->ptid, &lp->signalled);
   if (!WIFSTOPPED (status))
@@ -3329,12 +3330,18 @@ linux_nat_wait_1 (ptid_t ptid, struct target_waitstatus *ourstatus,
      moment at which we know its PID.  */
   if (ptid.is_pid () && find_lwp_pid (ptid) == nullptr)
     {
-      ptid_t lwp_ptid (ptid.pid (), ptid.pid ());
+      /* Unless we already did and this is simply a request to wait for a
+	 particular inferior.  */
+      inferior *inf = find_inferior_ptid (linux_target, ptid);
+      if (inf && inf->find_thread (ptid))
+	{
+	  ptid_t lwp_ptid (ptid.pid (), ptid.pid ());
 
-      /* Upgrade the main thread's ptid.  */
-      thread_change_ptid (linux_target, ptid, lwp_ptid);
-      lp = add_initial_lwp (lwp_ptid);
-      lp->resumed = 1;
+	  /* Upgrade the main thread's ptid.  */
+	  thread_change_ptid (linux_target, ptid, lwp_ptid);
+	  lp = add_initial_lwp (lwp_ptid);
+	  lp->resumed = 1;
+	}
     }
 
   /* Make sure SIGCHLD is blocked until the sigsuspend below.  */
diff --git a/gdb/remote.c b/gdb/remote.c
index a09ba4d715d..49abd4e4376 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -7825,12 +7825,24 @@ remote_target::remote_notif_remove_queued_reply (ptid_t ptid)
 {
   remote_state *rs = get_remote_state ();
 
+  auto pred = [=] (const stop_reply_up &event)
+  {
+    /* A null ptid should only happen if we have a single process.  It
+       wouldn't match the process ptid, though, so let's check this case
+       separately.  */
+    if ((event->ptid == null_ptid) && ptid.is_pid ())
+      return true;
+
+    /* A minus one ptid should only happen for events that match
+       everything.  It wouldn't match a process or thread ptid, though, so
+       let's check this case separately.  */
+    if (event->ptid == minus_one_ptid)
+      return true;
+
+    return event->ptid.matches (ptid);
+  };
   auto iter = std::find_if (rs->stop_reply_queue.begin (),
-			    rs->stop_reply_queue.end (),
-			    [=] (const stop_reply_up &event)
-			    {
-			      return event->ptid.matches (ptid);
-			    });
+			    rs->stop_reply_queue.end (), pred);
   stop_reply_up result;
   if (iter != rs->stop_reply_queue.end ())
     {
-- 
2.34.1

Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928

[PATCH v2 6/6] gdb, btrace, infrun: per-inferior run-control

[Markus Metzger]

While recording is already per inferior, run-control isn't.  As soon as
any thread in any inferior is replaying, no other inferior can be resumed.

This is controlled by many calls to record_is_replaying(minus_one_ptid).
Instead of minus_one_ptid, pass the ptid of the inferior to be checked.
---
 gdb/infrun.c                                | 17 ++++++++------
 gdb/record-btrace.c                         | 26 +++++----------------
 gdb/testsuite/gdb.btrace/multi-inferior.c   | 10 +++++++-
 gdb/testsuite/gdb.btrace/multi-inferior.exp | 19 +++++++++++++++
 4 files changed, 44 insertions(+), 28 deletions(-)

diff --git a/gdb/infrun.c b/gdb/infrun.c
index 9ca0571065c..a237d970030 100644
--- a/gdb/infrun.c
+++ b/gdb/infrun.c
@@ -2399,7 +2399,8 @@ user_visible_resume_ptid (int step)
       resume_ptid = inferior_ptid;
     }
   else if ((scheduler_mode == schedlock_replay)
-	   && target_record_will_replay (minus_one_ptid, execution_direction))
+	   && target_record_will_replay (ptid_t (inferior_ptid.pid ()),
+					 execution_direction))
     {
       /* User-settable 'scheduler' mode requires solo thread resume in replay
 	 mode.  */
@@ -3117,15 +3118,17 @@ clear_proceed_status (int step)
      This is a convenience feature to not require the user to explicitly
      stop replaying the other threads.  We're assuming that the user's
      intent is to resume tracing the recorded process.  */
+  ptid_t resume_ptid = user_visible_resume_ptid (step);
   if (!non_stop && scheduler_mode == schedlock_replay
-      && target_record_is_replaying (minus_one_ptid)
-      && !target_record_will_replay (user_visible_resume_ptid (step),
-				     execution_direction))
-    target_record_stop_replaying ();
+      && target_record_is_replaying (ptid_t (resume_ptid.pid ()))
+      && !target_record_will_replay (resume_ptid, execution_direction))
+    {
+      target_record_stop_replaying ();
+      resume_ptid = user_visible_resume_ptid (step);
+    }
 
   if (!non_stop && inferior_ptid != null_ptid)
     {
-      ptid_t resume_ptid = user_visible_resume_ptid (step);
       process_stratum_target *resume_target
 	= user_visible_resume_target (resume_ptid);
 
@@ -3204,7 +3207,7 @@ schedlock_applies (struct thread_info *tp)
 	  || (scheduler_mode == schedlock_step
 	      && tp->control.stepping_command)
 	  || (scheduler_mode == schedlock_replay
-	      && target_record_will_replay (minus_one_ptid,
+	      && target_record_will_replay (ptid_t (tp->inf->pid),
 					    execution_direction)));
 }
 
diff --git a/gdb/record-btrace.c b/gdb/record-btrace.c
index 53ed481eb4d..3f9e19b1a02 100644
--- a/gdb/record-btrace.c
+++ b/gdb/record-btrace.c
@@ -121,7 +121,6 @@ class record_btrace_target final : public target_ops
   ptid_t wait (ptid_t, struct target_waitstatus *, target_wait_flags) override;
 
   void stop (ptid_t) override;
-  void update_thread_list () override;
   bool thread_alive (ptid_t ptid) override;
   void goto_record_begin () override;
   void goto_record_end () override;
@@ -2159,7 +2158,7 @@ record_btrace_target::resume (ptid_t ptid, int step, enum gdb_signal signal)
      make progress, we may need to explicitly move replaying threads to the end
      of their execution history.  */
   if ((::execution_direction != EXEC_REVERSE)
-      && !record_is_replaying (minus_one_ptid))
+      && !record_is_replaying (ptid_t (ptid.pid ())))
     {
       this->beneath ()->resume (ptid, step, signal);
       return;
@@ -2542,7 +2541,7 @@ record_btrace_target::wait (ptid_t ptid, struct target_waitstatus *status,
 
   /* As long as we're not replaying, just forward the request.  */
   if ((::execution_direction != EXEC_REVERSE)
-      && !record_is_replaying (minus_one_ptid))
+      && !record_is_replaying (ptid_t (ptid.pid ())))
     {
       return this->beneath ()->wait (ptid, status, options);
     }
@@ -2663,7 +2662,7 @@ record_btrace_target::stop (ptid_t ptid)
 
   /* As long as we're not replaying, just forward the request.  */
   if ((::execution_direction != EXEC_REVERSE)
-      && !record_is_replaying (minus_one_ptid))
+      && !record_is_replaying (ptid_t (ptid.pid ())))
     {
       this->beneath ()->stop (ptid);
     }
@@ -2693,7 +2692,7 @@ record_btrace_target::can_execute_reverse ()
 bool
 record_btrace_target::stopped_by_sw_breakpoint ()
 {
-  if (record_is_replaying (minus_one_ptid))
+  if (record_is_replaying (ptid_t (inferior_ptid.pid ())))
     {
       struct thread_info *tp = inferior_thread ();
 
@@ -2708,7 +2707,7 @@ record_btrace_target::stopped_by_sw_breakpoint ()
 bool
 record_btrace_target::stopped_by_hw_breakpoint ()
 {
-  if (record_is_replaying (minus_one_ptid))
+  if (record_is_replaying (ptid_t (inferior_ptid.pid ())))
     {
       struct thread_info *tp = inferior_thread ();
 
@@ -2718,26 +2717,13 @@ record_btrace_target::stopped_by_hw_breakpoint ()
   return this->beneath ()->stopped_by_hw_breakpoint ();
 }
 
-/* The update_thread_list method of target record-btrace.  */
-
-void
-record_btrace_target::update_thread_list ()
-{
-  /* We don't add or remove threads during replay.  */
-  if (record_is_replaying (minus_one_ptid))
-    return;
-
-  /* Forward the request.  */
-  this->beneath ()->update_thread_list ();
-}
-
 /* The thread_alive method of target record-btrace.  */
 
 bool
 record_btrace_target::thread_alive (ptid_t ptid)
 {
   /* We don't add or remove threads during replay.  */
-  if (record_is_replaying (minus_one_ptid))
+  if (record_is_replaying (ptid_t (ptid.pid ())))
     return true;
 
   /* Forward the request.  */
diff --git a/gdb/testsuite/gdb.btrace/multi-inferior.c b/gdb/testsuite/gdb.btrace/multi-inferior.c
index fb4ffc22a17..6f1052a7f25 100644
--- a/gdb/testsuite/gdb.btrace/multi-inferior.c
+++ b/gdb/testsuite/gdb.btrace/multi-inferior.c
@@ -15,8 +15,16 @@
    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
 
+static int
+fun (void)
+{
+  int x = fun (); /* fun.1 */
+  return x;       /* fun.2 */
+}
+
 int
 main (void)
 {
-  return 0;
+  int x = fun (); /* main.1 */
+  return x;       /* main.2 */
 }
diff --git a/gdb/testsuite/gdb.btrace/multi-inferior.exp b/gdb/testsuite/gdb.btrace/multi-inferior.exp
index 174d38364a4..df7f423a088 100644
--- a/gdb/testsuite/gdb.btrace/multi-inferior.exp
+++ b/gdb/testsuite/gdb.btrace/multi-inferior.exp
@@ -39,6 +39,8 @@ with_test_prefix "inferior 1" {
     }
 
     gdb_test_no_output "record btrace"
+    gdb_test "step 4" "fun\.1.*"
+    gdb_test "reverse-step" "fun\.1.*"
 }
 
 with_test_prefix "inferior 2" {
@@ -51,4 +53,21 @@ with_test_prefix "inferior 2" {
     }
 
     gdb_test_no_output "record btrace"
+    gdb_test "step 4" "fun\.1.*"
+    gdb_test "reverse-step" "fun\.1.*"
+
+    gdb_test "info record" "Replay in progress.*"
+    gdb_test "record stop" "Process record is stopped.*"
+
+    gdb_test "step" "fun\.1.*"
+}
+
+with_test_prefix "inferior 1" {
+    gdb_test "inferior 1" "Switching to inferior 1.*"
+
+    gdb_test "info record" "Replay in progress.*"
+    gdb_test "reverse-finish" "fun\.1.*"
+    gdb_test "record goto end" "fun\.1.*"
+    gdb_test "step 2" "fun\.1.*"
+    gdb_test "reverse-step 3"
 }
-- 
2.34.1

Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928

[PING] [PATCH v2 0/6] fix PR gdb/19340

[Metzger, Markus T]

Kindly pinging.

Markus.

>-----Original Message-----
>From: Metzger, Markus T <markus.t.metzger@intel.com>
>Sent: Thursday, April 11, 2024 7:26 AM
>To: gdb-patches@sourceware.org
>Cc: pedro@palves.net
>Subject: [PATCH v2 0/6] fix PR gdb/19340
>
>Fix PR gdb/19340 by stopping replaying the current thread before disabling
>recording.
>
>While writing the test for this, I wondered whether it would also work if
>there was more than one process and if some were recording while others
>were replaying.
>
>It turned out that recording one process while some other process is
>replaying doesn't work.  You first have to stop replaying everything
>before you can continue recording.  Since btrace is per inferior, this
>seems like an unnecessary restriction.
>
>The first patch fixes gdb/pr19340; the rest makes recording work together
>with replaying on inferior level.
>
>The most prominent change is probably that do_target_wait() no longer
>silently switches inferiors.  This infrun change requires global
>maintainer approval.
>
>Changes to v1:
>  - fixed a fail in a newly added test
>  - fixed fails in patch 5, which also caused the patch to get renamed
>
>Markus Metzger (6):
>  gdb, btrace: fix pr19340
>  gdb, btrace: simplify gdb.btrace/multi-inferior.exp
>  gdb, btrace: remove record_btrace_target::supports_*()
>  gdb, btrace: set wait status to ignore if nothing is moving
>  gdb, infrun: fix silent inferior switch in do_target_wait()
>  gdb, btrace, infrun: per-inferior run-control
>
> gdb/infrun.c                                | 63 ++++++++++++++---
> gdb/linux-nat.c                             | 17 +++--
> gdb/record-btrace.c                         | 78 +++++++--------------
> gdb/remote.c                                | 22 ++++--
> gdb/testsuite/gdb.btrace/multi-inferior.c   | 10 ++-
> gdb/testsuite/gdb.btrace/multi-inferior.exp | 33 ++++-----
> gdb/testsuite/gdb.btrace/step.exp           | 22 ++++--
> 7 files changed, 150 insertions(+), 95 deletions(-)
>
>--
>2.34.1

Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928