Huaixin Chang 9fa3b0bd99 sched: Defend cfs and rt bandwidth quota against overflow
[ Upstream commit d505b8af58912ae1e1a211fabc9995b19bd40828 ]

When users write some huge number into cpu.cfs_quota_us or
cpu.rt_runtime_us, overflow might happen during to_ratio() shifts of
schedulable checks.

to_ratio() could be altered to avoid unnecessary internal overflow, but
min_cfs_quota_period is less than 1 << BW_SHIFT, so a cutoff would still
be needed. Set a cap MAX_BW for cfs_quota_us and rt_runtime_us to
prevent overflow.

Signed-off-by: Huaixin Chang <changhuaixin@linux.alibaba.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ben Segall <bsegall@google.com>
Link: https://lkml.kernel.org/r/20200425105248.60093-1-changhuaixin@linux.alibaba.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-06-22 09:31:07 +02:00
..
2019-06-17 12:12:27 +02:00
2019-06-17 12:12:27 +02:00
2019-06-24 19:19:53 +02:00