1 files changed, 2 insertions, 0 deletions

diff --git a/firmware/kernel/mutex.c b/firmware/kernel/mutex.c
index cb9e6816b8..b1ae3e9e54 100644
--- a/firmware/kernel/mutex.c
+++ b/firmware/kernel/mutex.c
@@ -39,6 +39,8 @@ void mutex_init(struct mutex *m)
 /* Gain ownership of a mutex object or block until it becomes free */
 void mutex_lock(struct mutex *m)
 {
+    ASSERT_CPU_MODE(CPU_MODE_THREAD_CONTEXT);
+
     struct thread_entry *current = __running_self_entry();
 
     if(current == m->blocker.thread)