From b9dca1e0fcb696716840a3bc8f20a6941b484dbf Mon Sep 17 00:00:00 2001
From: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Date: Wed, 17 Oct 2007 16:55:11 +0200
Subject: [PATCH] sched: fix new task startup crash
Child task may be added on a different cpu that the one on which parent
is running. In which case, task_new_fair() should check whether the new
born task's parent entity should be added as well on the cfs_rq.
Patch below fixes the problem in task_new_fair.
This could fix the put_prev_task_fair() crashes reported.
Reported-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Reported-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---
kernel/sched.c | 2 +-
kernel/sched_fair.c | 6 +-----
2 files changed, 2 insertions(+), 6 deletions(-)
diff --git a/kernel/sched.c b/kernel/sched.c
index 975436435b427..0ec9521a8e704 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -1712,7 +1712,7 @@ void fastcall wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
p->prio = effective_prio(p);
- if (!p->sched_class->task_new || !current->se.on_rq || !rq->cfs.curr) {
+ if (!p->sched_class->task_new || !current->se.on_rq) {
activate_task(rq, p, 0);
} else {
/*
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index a17b785d7000c..166ed6db600b0 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -1031,12 +1031,8 @@ static void task_new_fair(struct rq *rq, struct task_struct *p)
swap(curr->vruntime, se->vruntime);
}
- update_stats_enqueue(cfs_rq, se);
- check_spread(cfs_rq, se);
- check_spread(cfs_rq, curr);
- __enqueue_entity(cfs_rq, se);
- account_entity_enqueue(cfs_rq, se);
se->peer_preempt = 0;
+ enqueue_task_fair(rq, p, 0);
resched_task(rq->curr);
}
--
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