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Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

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Pull scheduler fix from Ingo Molnar:
 "Fix a crash that can trigger when racing with CPU hotplug: we didn't
  use sched-domains data structures carefully enough in select_idle_cpu()"

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/fair: Fix sched domains NULL dereference in select_idle_sibling()
This commit is contained in:
Linus Torvalds 2016-10-18 09:53:59 -07:00
commit 2c11fc87ca
1 changed files with 8 additions and 3 deletions
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11
kernel/sched/fair.c
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@ -5471,13 +5471,18 @@ static inline int select_idle_smt(struct task_struct *p, struct sched_domain *sd
*/
static int select_idle_cpu(struct task_struct *p, struct sched_domain *sd, int target)
{
struct sched_domain *this_sd = rcu_dereference(*this_cpu_ptr(&sd_llc));
u64 avg_idle = this_rq()->avg_idle;
u64 avg_cost = this_sd->avg_scan_cost;
struct sched_domain *this_sd;
u64 avg_cost, avg_idle = this_rq()->avg_idle;
u64 time, cost;
s64 delta;
int cpu, wrap;
this_sd = rcu_dereference(*this_cpu_ptr(&sd_llc));
if (!this_sd)
return -1;
avg_cost = this_sd->avg_scan_cost;
/*
* Due to large variance we need a large fuzz factor; hackbench in
* particularly is sensitive here.