diff --git a/kernel/syscall.c b/kernel/syscall.c
index 515d5837..11c6f02b 100644
--- a/kernel/syscall.c
+++ b/kernel/syscall.c
@@ -2457,7 +2457,7 @@ static int ptrace_setoptions(int pid, int flags)
 	}
 
 	child = findthread_and_lock(pid, -1, &savelock, &irqstate);
-	if (!child || !child->ftn || !(child->ftn->ptrace | PT_TRACED)) {
+	if (!child || !child->ftn || !(child->ftn->ptrace & PT_TRACED)) {
 		ret = -ESRCH;
 		goto unlockout;
 	}