[ANNOUNCE] 3.10.15-rt11

From: Sebastian Andrzej Siewior
Date: Fri Oct 11 2013 - 17:04:48 EST

Dear RT folks!

I'm pleased to announce the v3.10.15-rt11 patch set.

Changes since v3.10.15-rt10
- two genirq patches: one was already in v3.8-rt ("genirq: Set irq
thread to RT priority on creation"). The second ("genirq: Set the irq
thread policy without checking CAP_SYS_NICE") ensures that the
priority is also assigned if the irq is requested in user contex. Patch
by Thomas Pfaff.
- A patch from Paul Gortmaker to compile PowerPC without RT
- Four patches from Paul Gortmaker to compile with SLAB while RT is
disabled.
- A fix for "sleeping from invalid context" in tty_ldisc. Reported by
Luis Claudio R. Goncalves.
- A fix for "sleeping from invalid context" in the drm layer triggered
by the i915 driver. Reported by Luis Claudio R. Goncalves.

Known issues:

- SLAB support not working

- The cpsw network driver shows some issues.

- bcache is disabled.

- an ancient race (since we got sleeping spinlocks) where the
TASK_TRACED state is temporary replaced while waiting on a rw
lock and the task can't be traced.

- livelock in sem_lock(). A race fix queued for 3.10+ fixes
the livelock issue as well, but it's not yet in 3.10.15.
Should someone trigger, please look at 5e9d5275 ("ipc/sem.c:
fix race in sem_lock()") or wait till it hits the stable queue.

The delta patch against v3.10.15-rt10 is appended below and can be found
here:
https://www.kernel.org/pub/linux/kernel/projects/rt/3.10/incr/patch-3.10.15-rt10-rt11.patch.xz

The RT patch against 3.10.15 can be found here:

https://www.kernel.org/pub/linux/kernel/projects/rt/3.10/patch-3.10.15-rt11.patch.xz

The split quilt queue is available at:

https://www.kernel.org/pub/linux/kernel/projects/rt/3.10/patches-3.10.15-rt11.tar.xz

Sebastian

diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index a47400d..87f730e 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -264,7 +264,7 @@ int __kprobes do_page_fault(struct pt_regs *regs, unsigned long address,
if (!arch_irq_disabled_regs(regs))
local_irq_enable();

- if (in_atomic() || mm == NULL || current->pagefault_disabled) {
+ if (in_atomic() || mm == NULL || pagefault_disabled()) {
if (!user_mode(regs)) {
rc = SIGSEGV;
goto bail;
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index f92da0a..434ea84 100644
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -628,11 +628,6 @@ int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc,
* code gets preempted or delayed for some reason.
*/
for (i = 0; i < DRM_TIMESTAMP_MAXRETRIES; i++) {
- /* Disable preemption to make it very likely to
- * succeed in the first iteration even on PREEMPT_RT kernel.
- */
- preempt_disable();
-
/* Get system timestamp before query. */
stime = ktime_get();

@@ -644,8 +639,6 @@ int drm_calc_vbltimestamp_from_scanoutpos(struct drm_device *dev, int crtc,
if (!drm_timestamp_monotonic)
mono_time_offset = ktime_get_monotonic_offset();

- preempt_enable();
-
/* Return as no-op if scanout query unsupported or failed. */
if (!(vbl_status & DRM_SCANOUTPOS_VALID)) {
DRM_DEBUG("crtc %d : scanoutpos query failed [%d].\n",
diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c
index 1afe192..bc4ffe4 100644
--- a/drivers/tty/tty_ldisc.c
+++ b/drivers/tty/tty_ldisc.c
@@ -197,9 +197,10 @@ static inline void tty_ldisc_put(struct tty_ldisc *ld)
WARN_ON(!atomic_dec_and_test(&ld->users));

ld->ops->refcount--;
+ raw_spin_unlock_irqrestore(&tty_ldisc_lock, flags);
+
module_put(ld->ops->owner);
kfree(ld);
- raw_spin_unlock_irqrestore(&tty_ldisc_lock, flags);
}

static void *tty_ldiscs_seq_start(struct seq_file *m, loff_t *pos)
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index c5c19ec..7d59fb1f9 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -923,9 +923,6 @@ static void irq_thread_dtor(struct callback_head *unused)
static int irq_thread(void *data)
{
struct callback_head on_exit_work;
- static const struct sched_param param = {
- .sched_priority = MAX_USER_RT_PRIO/2,
- };
struct irqaction *action = data;
struct irq_desc *desc = irq_to_desc(action->irq);
irqreturn_t (*handler_fn)(struct irq_desc *desc,
@@ -937,8 +934,6 @@ static int irq_thread(void *data)
else
handler_fn = irq_thread_fn;

- sched_setscheduler(current, SCHED_FIFO, &param);
-
init_task_work(&on_exit_work, irq_thread_dtor);
task_work_add(current, &on_exit_work, false);

@@ -1039,6 +1034,9 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
*/
if (new->thread_fn && !nested) {
struct task_struct *t;
+ static const struct sched_param param = {
+ .sched_priority = MAX_USER_RT_PRIO/2,
+ };

t = kthread_create(irq_thread, new, "irq/%d-%s", irq,
new->name);
@@ -1046,6 +1044,9 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
ret = PTR_ERR(t);
goto out_mput;
}
+
+ sched_setscheduler_nocheck(t, SCHED_FIFO, &param);
+
/*
* We keep the reference to the task struct even if
* the thread dies to avoid that the interrupt code
diff --git a/localversion-rt b/localversion-rt
index d79dde6..05c35cb 100644
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt10
+-rt11
diff --git a/mm/slab.c b/mm/slab.c
index 0a3d6d3..1e9330f 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -700,6 +700,12 @@ static inline struct array_cache *cpu_cache_get(struct kmem_cache *cachep)
return cachep->array[smp_processor_id()];
}

+static inline struct array_cache *cpu_cache_get_on_cpu(struct kmem_cache *cachep,
+ int cpu)
+{
+ return cachep->array[cpu];
+}
+
static size_t slab_mgmt_size(size_t nr_objs, size_t align)
{
return ALIGN(sizeof(struct slab)+nr_objs*sizeof(kmem_bufctl_t), align);
@@ -1233,11 +1239,11 @@ static int init_cache_node_node(int node)
cachep->node[node] = n;
}

- local_spin_lock_irq(slab_lock, &cachep->nodelists[node]->list_lock);
+ local_spin_lock_irq(slab_lock, &cachep->node[node]->list_lock);
cachep->node[node]->free_limit =
(1 + nr_cpus_node(node)) *
cachep->batchcount + cachep->num;
- local_spin_unlock_irq(slab_lock, &cachep->nodelists[node]->list_lock);
+ local_spin_unlock_irq(slab_lock, &cachep->node[node]->list_lock);
}
return 0;
}
@@ -2517,7 +2523,7 @@ static void drain_array(struct kmem_cache *cachep, struct kmem_cache_node *n,
struct array_cache *ac,
int force, int node);

-static void __do_drain(void *arg, unsigned int cpu)+static void __do_drain(void *arg, unsigned int cpu)
+static void __do_drain(void *arg, unsigned int cpu)
{
struct kmem_cache *cachep = arg;
struct array_cache *ac;
@@ -4058,7 +4064,7 @@ static int __do_tune_cpucache(struct kmem_cache *cachep, int limit,
&cachep->node[cpu_to_mem(i)]->list_lock);
free_block(cachep, ccold->entry, ccold->avail, cpu_to_mem(i));

- unlock_l3_and_free_delayed(&cachep->nodelists[cpu_to_mem(i)]->list_lock);
+ unlock_l3_and_free_delayed(&cachep->node[cpu_to_mem(i)]->list_lock);
kfree(ccold);
}
kfree(new);
diff --git a/mm/slab.h b/mm/slab.h
index 2e6c8b7..fc3c097 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -247,7 +247,11 @@ static inline struct kmem_cache *cache_from_obj(struct kmem_cache *s, void *x)
* The slab lists for all objects.
*/
struct kmem_cache_node {
+#ifdef CONFIG_SLAB
+ spinlock_t list_lock;
+#else
raw_spinlock_t list_lock;
+#endif

#ifdef CONFIG_SLAB
struct list_head slabs_partial; /* partial list first, better asm code */
--
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