[PATCH tip/core/rcu 03/15] rcu: Properly initialize ->boost_tasks on CPU offline

From: Paul E. McKenney
Date: Thu Aug 30 2012 - 17:44:51 EST


From: "Paul E. McKenney" <paul.mckenney@xxxxxxxxxx>

When rcu_preempt_offline_tasks() clears tasks from a leaf rcu_node
structure, it does not NULL out the structure's ->boost_tasks field.
This commit therefore fixes this issue.

Signed-off-by: Paul E. McKenney <paul.mckenney@xxxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
kernel/rcutree_plugin.h | 7 ++++---
1 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h
index 7f3244c..b1b4851 100644
--- a/kernel/rcutree_plugin.h
+++ b/kernel/rcutree_plugin.h
@@ -584,8 +584,11 @@ static int rcu_preempt_offline_tasks(struct rcu_state *rsp,
raw_spin_unlock(&rnp_root->lock); /* irqs still disabled */
}

+ rnp->gp_tasks = NULL;
+ rnp->exp_tasks = NULL;
#ifdef CONFIG_RCU_BOOST
- /* In case root is being boosted and leaf is not. */
+ rnp->boost_tasks = NULL;
+ /* In case root is being boosted and leaf was not. */
raw_spin_lock(&rnp_root->lock); /* irqs already disabled */
if (rnp_root->boost_tasks != NULL &&
rnp_root->boost_tasks != rnp_root->gp_tasks)
@@ -593,8 +596,6 @@ static int rcu_preempt_offline_tasks(struct rcu_state *rsp,
raw_spin_unlock(&rnp_root->lock); /* irqs still disabled */
#endif /* #ifdef CONFIG_RCU_BOOST */

- rnp->gp_tasks = NULL;
- rnp->exp_tasks = NULL;
return retval;
}

--
1.7.8

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