diff --git a/kernel/tsacct.c b/kernel/tsacct.c
index db44322..65a5036 100644
--- a/kernel/tsacct.c
+++ b/kernel/tsacct.c
@@ -36,7 +36,7 @@
 
 	/* calculate task elapsed time in timespec */
 	do_posix_clock_monotonic_gettime(&uptime);
-	ts = timespec_sub(uptime, current->group_leader->start_time);
+	ts = timespec_sub(uptime, tsk->start_time);
 	/* rebase elapsed time to usec */
 	ac_etime = timespec_to_ns(&ts);
 	do_div(ac_etime, NSEC_PER_USEC);
@@ -58,7 +58,10 @@
 	stats->ac_uid	 = tsk->uid;
 	stats->ac_gid	 = tsk->gid;
 	stats->ac_pid	 = tsk->pid;
-	stats->ac_ppid	 = (tsk->parent) ? tsk->parent->pid : 0;
+	rcu_read_lock();
+	stats->ac_ppid	 = pid_alive(tsk) ?
+				rcu_dereference(tsk->real_parent)->tgid : 0;
+	rcu_read_unlock();
 	stats->ac_utime	 = cputime_to_msecs(tsk->utime) * USEC_PER_MSEC;
 	stats->ac_stime	 = cputime_to_msecs(tsk->stime) * USEC_PER_MSEC;
 	stats->ac_minflt = tsk->min_flt;