From f895c8244f61a24d7d8661a033324706940bfef5 Mon Sep 17 00:00:00 2001
From: Pedro Alves <pedro@palves.net>
Date: Thu, 24 Apr 2025 20:09:16 +0100
Subject: [PATCH 1/2] Fix test races

Change-Id: Ia98a3195282a82fc68104f61cba1216bf0a296a0
---
 .../gdb.threads/info-threads-stopped.c        | 27 +++++----
 .../gdb.threads/info-threads-stopped.exp      | 56 ++++++++++---------
 2 files changed, 42 insertions(+), 41 deletions(-)

diff --git a/gdb/testsuite/gdb.threads/info-threads-stopped.c b/gdb/testsuite/gdb.threads/info-threads-stopped.c
index 2c38ecca074..2c4cd854bb7 100644
--- a/gdb/testsuite/gdb.threads/info-threads-stopped.c
+++ b/gdb/testsuite/gdb.threads/info-threads-stopped.c
@@ -22,30 +22,29 @@
 
 #define NUM 4
 
-volatile int should_spin = 1;
+static pthread_barrier_t threads_started_barrier;
 
 static void
-something ()
+stop_here ()
 {
 }
 
 static void
 spin ()
 {
-  while (should_spin)
+  while (1)
     usleep (1);
 }
 
 static void *
 work (void *arg)
 {
-  int id = *((int *) arg);
+  int id = *(int *) arg;
 
-  /* Sleep a bit to give the other threads a chance to run.  */
-  usleep (1);
+  pthread_barrier_wait (&threads_started_barrier);
 
   if (id % 2 == 0)
-    something (); /* break-here */
+    stop_here ();
   else
     spin ();
 
@@ -59,20 +58,20 @@ main ()
   alarm (10);
 
   pthread_t threads[NUM];
-  void *thread_result;
   int ids[NUM];
 
+  pthread_barrier_init (&threads_started_barrier, NULL, NUM + 1);
+
   for (int i = 0; i < NUM; i++)
     {
-      ids[i] = i + 2;
-      pthread_create (&threads[i], NULL, work, &(ids[i]));
+      ids[i] = i;
+      pthread_create (&threads[i], NULL, work, &ids[i]);
     }
 
-  sleep (10);
-  should_spin = 0;
+  /* Wait until all threads are seen running.  */
+  pthread_barrier_wait (&threads_started_barrier);
 
-  for (int i = 0; i < NUM; i++)
-    pthread_join(threads[i], &thread_result);
+  stop_here ();
 
   return 0;
 }
diff --git a/gdb/testsuite/gdb.threads/info-threads-stopped.exp b/gdb/testsuite/gdb.threads/info-threads-stopped.exp
index 37d6622697c..d554bd7ef2c 100644
--- a/gdb/testsuite/gdb.threads/info-threads-stopped.exp
+++ b/gdb/testsuite/gdb.threads/info-threads-stopped.exp
@@ -27,28 +27,29 @@ save_vars { GDBFLAGS } {
     clean_restart $binfile
 }
 
-gdb_breakpoint "something"
-gdb_run_cmd
+if ![runto_main] {
+    return -1
+}
+
+gdb_breakpoint "stop_here"
+gdb_test_multiple "continue -a&" "" {
+    -re "Continuing.\r\n$gdb_prompt " {
+	pass $gdb_test_name
+    }
+}
 
-# Two threads hit the bp.
+set expected_hits 3
 set fill "\[^\r\n\]+"
 set num_hits 0
 gdb_test_multiple "" "hit the breakpoint" -lbl {
-    -re "\r\nThread ${fill} hit Breakpoint 1${fill}" {
+    -re "\r\nThread ${fill} hit Breakpoint ${decimal}," {
 	incr num_hits
-	if {$num_hits < 2} {
+	if {$num_hits < $expected_hits} {
 	    exp_continue
 	}
     }
-    -re "\r\n$gdb_prompt " {
-	exp_continue
-    }
 }
-gdb_assert {$num_hits == 2} "two threads hit the bp"
-
-# We are in non-stop mode.
-# Send a simple command to resync the command prompt.
-gdb_test "p 42" " = 42"
+gdb_assert {$num_hits == $expected_hits} "expected threads hit the bp"
 
 # Count the number of running/stopped threads reported
 # by the "info threads" command.  We also capture thread ids
@@ -56,36 +57,37 @@ gdb_test "p 42" " = 42"
 set running_tid "invalid"
 set stopped_tid "invalid"
 
+set eol "(?=\r\n)"
+
 foreach flag {"" "-stopped"} {
     set num_running 0
     set num_stopped 0
-    gdb_test_multiple "info threads $flag" "info threads $flag" {
-	-re "Id${fill}Target Id${fill}Frame${fill}" {
+    gdb_test_multiple "info threads $flag" "info threads $flag" -lbl {
+	-re "Id${fill}Target Id${fill}Frame${fill}${eol}" {
 	    exp_continue
 	}
-	-re "^\r\n. (${decimal})${fill}Thread ${fill}.running." {
+	-re "^\r\n. (${decimal})${fill}Thread ${fill}.running.${eol}" {
 	    incr num_running
 	    set running_tid $expect_out(1,string)
 	    exp_continue
 	}
-	-re "^\r\n. (${decimal})${fill}Thread ${fill}something ${fill}${srcfile}:${decimal}" {
+	-re "^\r\n. (${decimal})${fill}Thread ${fill}stop_here ${fill}${srcfile}:${decimal}${fill}${eol}" {
 	    incr num_stopped
 	    set stopped_tid $expect_out(1,string)
 	    exp_continue
 	}
 	-re "^\r\n$gdb_prompt $" {
-	    gdb_assert {$num_stopped == 2} "$gdb_test_name: num stopped"
-	    if {$flag eq ""} {
-		gdb_assert {$num_running == 3} "$gdb_test_name: num running"
-	    } else {
-		gdb_assert {$num_running == 0} "$gdb_test_name: num running"
-	    }
+	    pass $gdb_test_name
 	}
     }
 }
 
-gdb_assert {$running_tid != "invalid"} "found a running thread"
-gdb_assert {$stopped_tid != "invalid"} "found a stopped thread"
+gdb_assert {$num_stopped == 3} "num stopped"
+if {$flag eq ""} {
+    gdb_assert {$num_running == 2} "num running"
+} else {
+    gdb_assert {$num_running == 0} "num running"
+}
 
 # Test specifying thread ids.
 gdb_test "info threads -stopped $running_tid" \
@@ -97,11 +99,11 @@ set ws "\[ \t\]+"
 gdb_test "info threads -stopped $stopped_tid" \
     [multi_line \
 	 "${ws}Id${ws}Target Id${ws}Frame${ws}" \
-	 "${ws}${stopped_tid}${ws}Thread ${fill} something ${fill}"] \
+	 "${ws}${stopped_tid}${ws}Thread ${fill} stop_here ${fill}"] \
     "info thread -stopped for a stopped thread"
 
 gdb_test "info threads -stopped $running_tid $stopped_tid" \
     [multi_line \
 	 "${ws}Id${ws}Target Id${ws}Frame${ws}" \
-	 "${ws}${stopped_tid}${ws}Thread ${fill} something ${fill}"] \
+	 "${ws}${stopped_tid}${ws}Thread ${fill} stop_here ${fill}"] \
     "info thread -stopped for a running and a stopped thread"

base-commit: e32b976a152894c00a01e4e0a48cd1f1d82d1d39
prerequisite-patch-id: 38786aad181a17816a63708dcae88f8bffed5469
prerequisite-patch-id: f64471d0b4bbbb7cb787ae826e654baf8c1a5bf3
-- 
2.49.0