From: Thomas Gleixner on
Linus,

Please pull the latest core-fixes-for-linus git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip.git core-fixes-for-linus

Thanks,

tglx

------------------>
Daniel J Blueman (1):
rcu: apply RCU protection to wake_affine()

Paul E. McKenney (1):
idr: fix RCU lockdep splat in idr_get_next()

Peter Zijlstra (1):
sched: silence PROVE_RCU in sched_fork()


kernel/sched.c | 9 +++++++++
kernel/sched_fair.c | 2 ++
lib/idr.c | 4 ++--
3 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/kernel/sched.c b/kernel/sched.c
index f8b8996..a2d215d 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -2494,7 +2494,16 @@ void sched_fork(struct task_struct *p, int clone_flags)
if (p->sched_class->task_fork)
p->sched_class->task_fork(p);

+ /*
+ * The child is not yet in the pid-hash so no cgroup attach races,
+ * and the cgroup is pinned to this child due to cgroup_fork()
+ * is ran before sched_fork().
+ *
+ * Silence PROVE_RCU.
+ */
+ rcu_read_lock();
set_task_cpu(p, cpu);
+ rcu_read_unlock();

#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
if (likely(sched_info_on()))
diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c
index eed35ed..a878b53 100644
--- a/kernel/sched_fair.c
+++ b/kernel/sched_fair.c
@@ -1240,6 +1240,7 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync)
* effect of the currently running task from the load
* of the current CPU:
*/
+ rcu_read_lock();
if (sync) {
tg = task_group(current);
weight = current->se.load.weight;
@@ -1275,6 +1276,7 @@ static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync)
balanced = this_eff_load <= prev_eff_load;
} else
balanced = true;
+ rcu_read_unlock();

/*
* If the currently running task will sleep within
diff --git a/lib/idr.c b/lib/idr.c
index c1a2069..7f1a4f0 100644
--- a/lib/idr.c
+++ b/lib/idr.c
@@ -602,7 +602,7 @@ void *idr_get_next(struct idr *idp, int *nextidp)
/* find first ent */
n = idp->layers * IDR_BITS;
max = 1 << n;
- p = rcu_dereference(idp->top);
+ p = rcu_dereference_raw(idp->top);
if (!p)
return NULL;

@@ -610,7 +610,7 @@ void *idr_get_next(struct idr *idp, int *nextidp)
while (n > 0 && p) {
n -= IDR_BITS;
*paa++ = p;
- p = rcu_dereference(p->ary[(id >> n) & IDR_MASK]);
+ p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]);
}

if (p) {
--
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