提交 85b088e9 编写于 作者: M Michal Nazarewicz 提交者: Ingo Molnar

sched/fair: Avoid integer overflow

sa->runnable_avg_sum is of type u32 but after shifting it by NICE_0_SHIFT
bits it is promoted to u64.  This of course makes no sense, since the
result will never be more then 32-bit long.  Casting sa->runnable_avg_sum
to u64 before it is shifted, fixes this problem.
Reviewed-by: NBen Segall <bsegall@google.com>
Signed-off-by: NMichal Nazarewicz <mina86@mina86.com>
Signed-off-by: NPeter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1384112521-25177-1-git-send-email-mpn@google.comSigned-off-by: NIngo Molnar <mingo@kernel.org>
上级 911b2898
......@@ -2178,7 +2178,7 @@ static inline void __update_tg_runnable_avg(struct sched_avg *sa,
long contrib;
/* The fraction of a cpu used by this cfs_rq */
contrib = div_u64(sa->runnable_avg_sum << NICE_0_SHIFT,
contrib = div_u64((u64)sa->runnable_avg_sum << NICE_0_SHIFT,
sa->runnable_avg_period + 1);
contrib -= cfs_rq->tg_runnable_contrib;
......
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