Messages in this thread Patch in this message | | | Date | Tue, 18 Oct 2016 13:17:20 +0200 | From | Ingo Molnar <> | Subject | [GIT PULL] scheduler fix |
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Linus,
Please pull the latest sched-urgent-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git sched-urgent-for-linus
# HEAD: 9cfb38a7ba5a9c27c1af8093fb1af4b699c0a441 sched/fair: Fix sched domains NULL dereference in select_idle_sibling()
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().
Thanks,
Ingo
------------------> Wanpeng Li (1): sched/fair: Fix sched domains NULL dereference in select_idle_sibling()
kernel/sched/fair.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 502e95a6e927..8b03fb5d1b9e 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.
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