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Subject[GIT PULL] scheduler fixes for v3.15
Linus,

Please pull the latest sched-urgent-for-linus git tree from:

git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git sched-urgent-for-linus

# HEAD: 09dc4ab03936df5c5aa711d27c81283c6d09f495 sched/fair: Fix tg_set_cfs_bandwidth() deadlock on rq->lock

Four misc fixes: each was deemed serious enough to warrant v3.15
inclusion.

Thanks,

Ingo

------------------>
Kirill Tkhai (1):
sched/dl: Fix race in dl_task_timer()

Richard Weinberger (1):
sched: Fix sched_policy < 0 comparison

Roman Gushchin (1):
sched/fair: Fix tg_set_cfs_bandwidth() deadlock on rq->lock

Steven Rostedt (1):
sched/numa: Fix use of spin_{un}lock_irq() when interrupts are disabled


kernel/sched/core.c | 5 ++---
kernel/sched/deadline.c | 10 +++++++++-
kernel/sched/fair.c | 15 ++++++++-------
kernel/sched/sched.h | 2 +-
4 files changed, 20 insertions(+), 12 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 86f3890..f3f48e7 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3685,7 +3685,7 @@ SYSCALL_DEFINE3(sched_setattr, pid_t, pid, struct sched_attr __user *, uattr,
if (retval)
return retval;

- if (attr.sched_policy < 0)
+ if ((int)attr.sched_policy < 0)
return -EINVAL;

rcu_read_lock();
@@ -7751,8 +7751,7 @@ static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota)
/* restart the period timer (if active) to handle new period expiry */
if (runtime_enabled && cfs_b->timer_active) {
/* force a reprogram */
- cfs_b->timer_active = 0;
- __start_cfs_bandwidth(cfs_b);
+ __start_cfs_bandwidth(cfs_b, true);
}
raw_spin_unlock_irq(&cfs_b->lock);

diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c
index 800e99b..14bc348 100644
--- a/kernel/sched/deadline.c
+++ b/kernel/sched/deadline.c
@@ -513,9 +513,17 @@ static enum hrtimer_restart dl_task_timer(struct hrtimer *timer)
struct sched_dl_entity,
dl_timer);
struct task_struct *p = dl_task_of(dl_se);
- struct rq *rq = task_rq(p);
+ struct rq *rq;
+again:
+ rq = task_rq(p);
raw_spin_lock(&rq->lock);

+ if (rq != task_rq(p)) {
+ /* Task was moved, retrying. */
+ raw_spin_unlock(&rq->lock);
+ goto again;
+ }
+
/*
* We need to take care of a possible races here. In fact, the
* task might have changed its scheduling policy to something
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 0fdb96d..8cbe2d2 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -1707,18 +1707,19 @@ no_join:
void task_numa_free(struct task_struct *p)
{
struct numa_group *grp = p->numa_group;
- int i;
void *numa_faults = p->numa_faults_memory;
+ unsigned long flags;
+ int i;

if (grp) {
- spin_lock_irq(&grp->lock);
+ spin_lock_irqsave(&grp->lock, flags);
for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++)
grp->faults[i] -= p->numa_faults_memory[i];
grp->total_faults -= p->total_numa_faults;

list_del(&p->numa_entry);
grp->nr_tasks--;
- spin_unlock_irq(&grp->lock);
+ spin_unlock_irqrestore(&grp->lock, flags);
rcu_assign_pointer(p->numa_group, NULL);
put_numa_group(grp);
}
@@ -3129,7 +3130,7 @@ static int assign_cfs_rq_runtime(struct cfs_rq *cfs_rq)
*/
if (!cfs_b->timer_active) {
__refill_cfs_bandwidth_runtime(cfs_b);
- __start_cfs_bandwidth(cfs_b);
+ __start_cfs_bandwidth(cfs_b, false);
}

if (cfs_b->runtime > 0) {
@@ -3308,7 +3309,7 @@ static void throttle_cfs_rq(struct cfs_rq *cfs_rq)
raw_spin_lock(&cfs_b->lock);
list_add_tail_rcu(&cfs_rq->throttled_list, &cfs_b->throttled_cfs_rq);
if (!cfs_b->timer_active)
- __start_cfs_bandwidth(cfs_b);
+ __start_cfs_bandwidth(cfs_b, false);
raw_spin_unlock(&cfs_b->lock);
}

@@ -3690,7 +3691,7 @@ static void init_cfs_rq_runtime(struct cfs_rq *cfs_rq)
}

/* requires cfs_b->lock, may release to reprogram timer */
-void __start_cfs_bandwidth(struct cfs_bandwidth *cfs_b)
+void __start_cfs_bandwidth(struct cfs_bandwidth *cfs_b, bool force)
{
/*
* The timer may be active because we're trying to set a new bandwidth
@@ -3705,7 +3706,7 @@ void __start_cfs_bandwidth(struct cfs_bandwidth *cfs_b)
cpu_relax();
raw_spin_lock(&cfs_b->lock);
/* if someone else restarted the timer then we're done */
- if (cfs_b->timer_active)
+ if (!force && cfs_b->timer_active)
return;
}

diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 456e492..369b4d6 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -278,7 +278,7 @@ extern void init_cfs_bandwidth(struct cfs_bandwidth *cfs_b);
extern int sched_group_set_shares(struct task_group *tg, unsigned long shares);

extern void __refill_cfs_bandwidth_runtime(struct cfs_bandwidth *cfs_b);
-extern void __start_cfs_bandwidth(struct cfs_bandwidth *cfs_b);
+extern void __start_cfs_bandwidth(struct cfs_bandwidth *cfs_b, bool force);
extern void unthrottle_cfs_rq(struct cfs_rq *cfs_rq);

extern void free_rt_sched_group(struct task_group *tg);

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