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| author |   Huaixin Chang <changhuaixin@linux.alibaba.com> | 2020-04-25 18:52:48 +0800 |
|---|---|---|
| committer |   Peter Zijlstra <peterz@infradead.org> | 2020-05-19 20:34:14 +0200 |
| commit | d505b8af58912ae1e1a211fabc9995b19bd40828 (patch) | |
| tree | d3eb4c4bd5d8670ee6aaaa56993a8ed366160de7 /kernel/sched/sched.h | |
| parent | sched/cpuacct: Fix charge cpuacct.usage_sys (diff) | |
| download | linux-dev-d505b8af58912ae1e1a211fabc9995b19bd40828.tar.xz linux-dev-d505b8af58912ae1e1a211fabc9995b19bd40828.zip | |
sched: Defend cfs and rt bandwidth quota against overflow
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
Diffstat (limited to 'kernel/sched/sched.h')
| -rw-r--r-- | kernel/sched/sched.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 2bd2a222318a..f7ab6334e992 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1915,6 +1915,8 @@ extern void init_dl_inactive_task_timer(struct sched_dl_entity *dl_se); #define BW_SHIFT 20 #define BW_UNIT (1 << BW_SHIFT) #define RATIO_SHIFT 8 +#define MAX_BW_BITS (64 - BW_SHIFT) +#define MAX_BW ((1ULL << MAX_BW_BITS) - 1) unsigned long to_ratio(u64 period, u64 runtime); extern void init_entity_runnable_average(struct sched_entity *se); |