test-coroutine: Regression test for yield bug

This adds a test for reentering a coroutine that previously yielded to a
coroutine that has meanwhile terminated.
Signed-off-by: NStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

tests/test-coroutine.c

@@ -13,6 +13,7 @@
 
 #include <glib.h>
 #include "block/coroutine.h"
+#include "block/coroutine_int.h"
 
 /*
  * Check that qemu_in_coroutine() works
@@ -122,6 +123,30 @@ static void test_yield(void)
     g_assert_cmpint(i, ==, 5); /* coroutine must yield 5 times */
 }
 
+static void coroutine_fn c2_fn(void *opaque)
+{
+    qemu_coroutine_yield();
+}
+
+static void coroutine_fn c1_fn(void *opaque)
+{
+    Coroutine *c2 = opaque;
+    qemu_coroutine_enter(c2, NULL);
+}
+
+static void test_co_queue(void)
+{
+    Coroutine *c1;
+    Coroutine *c2;
+
+    c1 = qemu_coroutine_create(c1_fn);
+    c2 = qemu_coroutine_create(c2_fn);
+
+    qemu_coroutine_enter(c1, c2);
+    memset(c1, 0xff, sizeof(Coroutine));
+    qemu_coroutine_enter(c2, NULL);
+}
+
 /*
  * Check that creation, enter, and return work
  */
@@ -343,6 +368,7 @@ static void perf_cost(void)
 int main(int argc, char **argv)
 {
     g_test_init(&argc, &argv, NULL);
+    g_test_add_func("/basic/co_queue", test_co_queue);
     g_test_add_func("/basic/lifecycle", test_lifecycle);
     g_test_add_func("/basic/yield", test_yield);
     g_test_add_func("/basic/nesting", test_nesting);