On 6/2/2017 4:27 PM, Jeffrey Hugo wrote:
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index d711093..84255ab 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -6737,10 +6737,10 @@ int can_migrate_task(struct task_struct *p, struct
lb_env *env)
* our sched_group. We may want to revisit it if we couldn't
* meet load balance goals by pulling other tasks on src_cpu.
*
- * Also avoid computing new_dst_cpu if we have already computed
- * one in current iteration.
+ * Avoid computing new_dst_cpu for NEWLY_IDLE or if we have
+ * already computed one in current iteration.
*/
- if (!env->dst_grpmask || (env->flags & LBF_DST_PINNED))
+ if (env->idle == CPU_NEWLY_IDLE || (env->flags &
LBF_DST_PINNED))
return 0;
Self NACK. This breaks active_load_balance_cpu_stop(). Looks like
env->idle == CPU_IDLE, but env->dst_grpmask is uninitialized, so it can
be NULL, which causes a null pointer dereference a few lines later.
I'm still having a look to see what makes sense to address the issue.
--
Jeffrey Hugo
Qualcomm Datacenter Technologies as an affiliate of Qualcomm
Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the
Code Aurora Forum, a Linux Foundation Collaborative Project.
