1 files changed, 1 insertions, 0 deletions
diff --git a/bsd-user/mmap.c b/bsd-user/mmap.c
index aca8764356..74ed00b9fe 100644
--- a/bsd-user/mmap.c
+++ b/bsd-user/mmap.c
@@ -32,6 +32,7 @@ void mmap_lock(void)
 
 void mmap_unlock(void)
 {
+    assert(mmap_lock_count > 0);
     if (--mmap_lock_count == 0) {
         pthread_mutex_unlock(&mmap_mutex);
     }