diff -r 374f6ed5f63c sys/kern/sys_futex.c
--- a/sys/kern/sys_futex.c	Fri Apr 17 18:26:28 2020 +0200
+++ b/sys/kern/sys_futex.c	Mon Apr 27 18:56:15 2020 +0000
@@ -885,7 +885,9 @@ futex_wait_abort(struct futex_wait *fw)
 
 	/* Now we can remove fw under the queue lock.  */
 	mutex_enter(&f->fx_qlock);
+	mutex_enter(&fw->fw_lock);
 	TAILQ_REMOVE(&f->fx_queue, fw, fw_entry);
+	mutex_exit(&fw->fw_lock);
 	mutex_exit(&f->fx_qlock);
 
 	/*