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authorLinus Torvalds <torvalds@linux-foundation.org>2016-10-18 18:53:59 +0200
committerLinus Torvalds <torvalds@linux-foundation.org>2016-10-18 18:53:59 +0200
commit2c11fc87caa9a60ada54f4bfc97f7b1abc38d7d0 (patch)
tree50a0899747507dd45861687cc58793ecc40d3734 /kernel
parentMerge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/ke... (diff)
parentsched/fair: Fix sched domains NULL dereference in select_idle_sibling() (diff)
downloadlinux-2c11fc87caa9a60ada54f4bfc97f7b1abc38d7d0.tar.xz
linux-2c11fc87caa9a60ada54f4bfc97f7b1abc38d7d0.zip
Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
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()
Diffstat (limited to 'kernel')
-rw-r--r--kernel/sched/fair.c11
1 files changed, 8 insertions, 3 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 2d4ad72f8f3c..76ee7de1859d 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -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.