diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c
index ccb0468..92a0380 100644
--- a/kernel/posix-cpu-timers.c
+++ b/kernel/posix-cpu-timers.c
@@ -486,6 +486,9 @@
  	struct task_struct *t = p;
 	unsigned int nthreads = atomic_read(&p->signal->live);
 
+	if (!nthreads)
+		return;
+
 	switch (clock_idx) {
 	default:
 		BUG();
@@ -1160,6 +1163,9 @@
 		unsigned long long sched_left, sched;
 		const unsigned int nthreads = atomic_read(&sig->live);
 
+		if (!nthreads)
+			return;
+
 		prof_left = cputime_sub(prof_expires, utime);
 		prof_left = cputime_sub(prof_left, stime);
 		prof_left = cputime_div(prof_left, nthreads);