[PATCH v4 06/11] gdb, remote: fix ptid matching for process-wide stop events

From: "Rohr, Stephan" <[email protected]>

If an inferior call results in a process event for a non-stop remote
target, GDB does not properly handle the event but is hanging.

Because GDB is evaluating a breakpoint condition, the corresponding
inferior call is evaluated w.r.t. the ptid of the current thread.
gdbserver sends a process exit event; the event is not matched by the
thread PTID and GDB hangs.

Fix this by matching a process event in 'stop_reply_queue' if there is
no matching thread event.  This ensures a thread event is prioritized
if both a thread event and a process event are queued and preserves the
current behavior.

Reproducible when running gdb.base/exit-in-condition.exp, on
native-extended-gdbserver with target-non-stop enabled.

export GDBFLAGS="-iex \"maint set target-non-stop on\""
make check TESTS="gdb.base/exit-in-condition.exp" \
    RUNTESTFLAGS="--target_board=native-extended-gdbserver GDBFLAGS='$GDBFLAGS'"
---
 gdb/remote.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/gdb/remote.c b/gdb/remote.c
index b27b1a1b6c0..b1bc1283b9a 100644
--- a/gdb/remote.c
+++ b/gdb/remote.c
@@ -8303,6 +8303,20 @@ remote_target::remote_notif_remove_queued_reply (ptid_t ptid)
 			    {
 			      return event->ptid.matches (ptid);
 			    });
+
+  /* Match process events if PTID is a thread and there is no matching event
+     queued.  Prioritize thread events to preserve the existing behavior.  */
+  if (iter == rs->stop_reply_queue.end ()
+      && ptid != minus_one_ptid
+      && !ptid.is_pid ())
+    iter = std::find_if (rs->stop_reply_queue.begin (),
+			 rs->stop_reply_queue.end (),
+			 [=] (const stop_reply_up &event)
+			 {
+			   return (event->ptid.is_pid ()
+			     && event->ptid.pid () == ptid.pid ());
+			 });
+
   stop_reply_up result;
   if (iter != rs->stop_reply_queue.end ())
     {
-- 
2.43.0

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