Just like we do in cpu_exec().

Reported-by: Max Filippov <jcmvbkbc@gmail.com>
Tested-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Emilio G. Cota <cota@braap.org>
---
 accel/tcg/cpu-exec.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c
index 55e0ca41c4..fefd955d66 100644
--- a/accel/tcg/cpu-exec.c
+++ b/accel/tcg/cpu-exec.c
@@ -266,6 +266,9 @@ void cpu_exec_step_atomic(CPUState *cpu)
 #ifndef CONFIG_SOFTMMU
         tcg_debug_assert(!have_mmap_lock());
 #endif
+        if (qemu_mutex_iothread_locked()) {
+            qemu_mutex_unlock_iothread();
+        }
         assert_no_pages_locked();
     }
 
-- 
2.17.1