Commit 1b012750 authored May 15, 2014 by Srivatsa Vaddagiri

sched: window-stats: Fix overflow bug



Multiplication over-flow possibility exists in update_task_ravg() when
updating task's window_start. That would lead to incorrect accounting
of task load. Fix the issue by using 64-bit arithmetic.

CRs-Fixed: 665706
Change-Id: I92651c41efa6121bb8fe102e495ae956127b237a
Signed-off-by: Srivatsa Vaddagiri <vatsa@codeaurora.org>

parent 19bd5134

kernel/sched/core.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -1457,7 +1457,8 @@ void update_task_ravg(struct task_struct p, struct rq rq, int update_sum)
		if (!update_sum)
		p->ravg.window_start = wallclock;
		else
		p->ravg.window_start += n * window_size;
		p->ravg.window_start += (u64)n *
		(u64)window_size;
		BUG_ON(p->ravg.window_start > wallclock);
		if (update_sum)
		update_history(rq, p, window_size, n);