diff options
| author | Chris Redpath <chris.redpath@arm.com> | 2015-03-12 20:10:45 +0900 |
|---|---|---|
| committer | Seung-Woo Kim <sw0312.kim@samsung.com> | 2016-12-14 13:42:01 +0900 |
| commit | 99b61b9a7433f8c1ee2713217dd454b3176e75f6 (patch) | |
| tree | d3d707ef544affca4dfa9adfa2ed034b4ba54401 /kernel | |
| parent | 2d70be8ea6158a1d08182535617f8fab8eed32be (diff) | |
sched: hmp: fix out-of-range CPU possible
If someone hotplugs all the little CPUs while another CPU is handling
a wakeup, we can potentially return new_cpu == NR_CPUS from
hmp_select_slower_cpu (which is called internally by
hmp_best_little_cpu as well). We will use this to deref the
per_cpu rq array in hmp_next_down_delay which can go boom.
Signed-off-by: Chris Redpath <chris.redpath@arm.com>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched/fair.c | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 7f05e5584265..33a6cdf9be0a 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -5946,7 +5946,11 @@ unlock: new_cpu = hmp_select_slower_cpu(p, prev_cpu); #endif - if (new_cpu != prev_cpu) { + /* + * we might have no suitable CPU + * in which case new_cpu == NR_CPUS + */ + if (new_cpu < NR_CPUS && new_cpu != prev_cpu) { hmp_next_down_delay(&p->se, new_cpu); trace_sched_hmp_migrate(p, new_cpu, HMP_MIGRATE_WAKEUP); return new_cpu; |