[PATCH][gdb] Fix assert in remote_async_get_pending_events_handler

[Tom de Vries <tdevries@suse.de>]

Hi,

Occassionally I run into the following assert:
...
(gdb) PASS: gdb.multi/multi-target-continue.exp: inferior 5
Remote debugging from host ::1, port 49990^M
Process multi-target-continue created; pid = 31241^M
src/gdb/remote-notif.c:113: internal-error: \
  void remote_async_get_pending_events_handler(gdb_client_data): \
  Assertion `target_is_non_stop_p ()' failed.^M
...

The assert checks target_is_non_stop_p, which is related to the current
target.

Fix this by changing the assert such that it checks non-stopness related to
the event it's handling.

Tested on x86_64-linux.

Any comments?

Thanks,
- Tom

[gdb] Fix assert in remote_async_get_pending_events_handler

2021-04-16  Simon Marchi  <simon.marchi@polymtl.ca>
	    Tom de Vries  <tdevries@suse.de>

	PR remote/27710
	* remote.c (remote_target_is_non_stop_p): New function.
	* remote.h (remote_target_is_non_stop_p): Declare.
	* remote-notif.c (remote_async_get_pending_events_handler): Fix assert
	to check non-stopness using notif_state->remote rather current target.

---
 gdb/remote-notif.c |  2 +-
 gdb/remote.c       | 11 +++++++++++
 gdb/remote.h       |  1 +
 3 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/gdb/remote-notif.c b/gdb/remote-notif.c
index 5a3e1395b76..4245015ae37 100644
--- a/gdb/remote-notif.c
+++ b/gdb/remote-notif.c
@@ -110,7 +110,7 @@ remote_async_get_pending_events_handler (gdb_client_data data)
 {
   remote_notif_state *notif_state = (remote_notif_state *) data;
   clear_async_event_handler (notif_state->get_pending_events_token);
-  gdb_assert (target_is_non_stop_p ());
+  gdb_assert (remote_target_is_non_stop_p (notif_state->remote));
   remote_notif_process (notif_state, NULL);
 }
 
diff --git a/gdb/remote.c b/gdb/remote.c
index 7429e1a86b3..2e365df9bba 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -14730,6 +14730,17 @@ remote_target::store_memtags (CORE_ADDR address, size_t len,
   return packet_check_result (rs->buf.data ()) == PACKET_OK;
 }
 
+/* Return true if remote target T is non-stop.  */
+
+bool
+remote_target_is_non_stop_p (remote_target *t)
+{
+  scoped_restore_current_thread restore_thread;
+  switch_to_target_no_thread (t);
+
+  return target_is_non_stop_p ();
+}
+
 #if GDB_SELF_TEST
 
 namespace selftests {
diff --git a/gdb/remote.h b/gdb/remote.h
index 18352ddb866..46bfa01fc79 100644
--- a/gdb/remote.h
+++ b/gdb/remote.h
@@ -77,4 +77,5 @@ extern int remote_register_number_and_offset (struct gdbarch *gdbarch,
 
 extern void remote_notif_get_pending_events (remote_target *remote,
 					     struct notif_client *np);
+extern bool remote_target_is_non_stop_p (remote_target *t);
 #endif