diff --git a/kernel/tsacct.c b/kernel/tsacct.c
index 658f638..c122131 100644
--- a/kernel/tsacct.c
+++ b/kernel/tsacct.c
@@ -39,7 +39,7 @@
 	ac_etime = timespec_to_ns(&ts);
 	do_div(ac_etime, NSEC_PER_USEC);
 	stats->ac_etime = ac_etime;
-	stats->ac_btime = xtime.tv_sec - ts.tv_sec;
+	stats->ac_btime = get_seconds() - ts.tv_sec;
 	if (thread_group_leader(tsk)) {
 		stats->ac_exitcode = tsk->exit_code;
 		if (tsk->flags & PF_FORKNOEXEC)