Sebastian,

On Tue, 11 Jul 2017, Thomas Gleixner wrote:
> On Tue, 11 Jul 2017, Sebastian Reichel wrote:
> So this crashes in do_raw_spin_unlock_irqrestore() !?! I just have to
> wonder how the raw_spin_lock() succeeded. That does not make any sense.

can you please apply the patch below on top of 4.12? It's a backport
isolating the resource request changes.

Thanks,

        tglx

8<----------------------
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -1198,6 +1198,18 @@ static int
        if (desc->irq_data.chip->flags & IRQCHIP_ONESHOT_SAFE)
                new->flags &= ~IRQF_ONESHOT;
 
+       mutex_lock(&desc->request_mutex);
+       if (!desc->action) {
+               ret = irq_request_resources(desc);
+               if (ret) {
+                       pr_err("Failed to request resources for %s (irq %d) on 
irqchip %s\n",
+                              new->name, irq, desc->irq_data.chip->name);
+                       goto out_mutex;
+               }
+       }
+
+       chip_bus_lock(desc);
+
        /*
         * The following block of code has to be executed atomically
         */
@@ -1298,13 +1310,6 @@ static int
        }
 
        if (!shared) {
-               ret = irq_request_resources(desc);
-               if (ret) {
-                       pr_err("Failed to request resources for %s (irq %d) on 
irqchip %s\n",
-                              new->name, irq, desc->irq_data.chip->name);
-                       goto out_mask;
-               }
-
                init_waitqueue_head(&desc->wait_for_threads);
 
                /* Setup the type (level, edge polarity) if configured: */
@@ -1312,10 +1317,8 @@ static int
                        ret = __irq_set_trigger(desc,
                                                new->flags & IRQF_TRIGGER_MASK);
 
-                       if (ret) {
-                               irq_release_resources(desc);
+                       if (ret)
                                goto out_mask;
-                       }
                }
 
                desc->istate &= ~(IRQS_AUTODETECT | IRQS_SPURIOUS_DISABLED | \
@@ -1373,6 +1376,8 @@ static int
        }
 
        raw_spin_unlock_irqrestore(&desc->lock, flags);
+       chip_bus_sync_unlock(desc);
+       mutex_unlock(&desc->request_mutex);
 
        /*
         * Strictly no need to wake it up, but hung_task complains
@@ -1402,6 +1407,13 @@ static int
 
 out_mask:
        raw_spin_unlock_irqrestore(&desc->lock, flags);
+       chip_bus_sync_unlock(desc);
+       if (!desc->action)
+               irq_release_resources(desc);
+
+out_mutex:
+       mutex_unlock(&desc->request_mutex);
+
        free_cpumask_var(mask);
 
 out_thread:
@@ -1443,9 +1455,7 @@ int setup_irq(unsigned int irq, struct i
        if (retval < 0)
                return retval;
 
-       chip_bus_lock(desc);
        retval = __setup_irq(irq, desc, act);
-       chip_bus_sync_unlock(desc);
 
        if (retval)
                irq_chip_pm_put(&desc->irq_data);
@@ -1469,6 +1479,7 @@ static struct irqaction *__free_irq(unsi
        if (!desc)
                return NULL;
 
+       mutex_lock(&desc->request_mutex);
        chip_bus_lock(desc);
        raw_spin_lock_irqsave(&desc->lock, flags);
 
@@ -1501,7 +1512,6 @@ static struct irqaction *__free_irq(unsi
        if (!desc->action) {
                irq_settings_clr_disable_unlazy(desc);
                irq_shutdown(desc);
-               irq_release_resources(desc);
        }
 
 #ifdef CONFIG_SMP
@@ -1543,6 +1553,11 @@ static struct irqaction *__free_irq(unsi
                }
        }
 
+       if (!desc->action)
+               irq_release_resources(desc);
+
+       mutex_unlock(&desc->request_mutex);
+
        irq_chip_pm_put(&desc->irq_data);
        module_put(desc->owner);
        kfree(action->secondary);
@@ -1699,9 +1714,7 @@ int request_threaded_irq(unsigned int ir
                return retval;
        }
 
-       chip_bus_lock(desc);
        retval = __setup_irq(irq, desc, action);
-       chip_bus_sync_unlock(desc);
 
        if (retval) {
                irq_chip_pm_put(&desc->irq_data);
@@ -1949,9 +1962,7 @@ int setup_percpu_irq(unsigned int irq, s
        if (retval < 0)
                return retval;
 
-       chip_bus_lock(desc);
        retval = __setup_irq(irq, desc, act);
-       chip_bus_sync_unlock(desc);
 
        if (retval)
                irq_chip_pm_put(&desc->irq_data);
@@ -2005,9 +2016,7 @@ int request_percpu_irq(unsigned int irq,
                return retval;
        }
 
-       chip_bus_lock(desc);
        retval = __setup_irq(irq, desc, action);
-       chip_bus_sync_unlock(desc);
 
        if (retval) {
                irq_chip_pm_put(&desc->irq_data);
--- a/include/linux/irqdesc.h
+++ b/include/linux/irqdesc.h
@@ -3,6 +3,7 @@
 
 #include <linux/rcupdate.h>
 #include <linux/kobject.h>
+#include <linux/mutex.h>
 
 /*
  * Core internal functions to deal with irq descriptors
@@ -45,6 +46,7 @@ struct pt_regs;
  *                     IRQF_FORCE_RESUME set
  * @rcu:               rcu head for delayed free
  * @kobj:              kobject used to represent this struct in sysfs
+ * @request_mutex:     mutex to protect request/free before locking desc->lock
  * @dir:               /proc/irq/ procfs entry
  * @name:              flow handler name for /proc/interrupts output
  */
@@ -92,6 +94,7 @@ struct irq_desc {
        struct rcu_head         rcu;
        struct kobject          kobj;
 #endif
+       struct mutex            request_mutex;
        int                     parent_irq;
        struct module           *owner;
        const char              *name;
--- a/kernel/irq/irqdesc.c
+++ b/kernel/irq/irqdesc.c
@@ -359,6 +359,7 @@ static struct irq_desc *alloc_desc(int i
 
        raw_spin_lock_init(&desc->lock);
        lockdep_set_class(&desc->lock, &irq_desc_lock_class);
+       mutex_init(&desc->request_mutex);
        init_rcu_head(&desc->rcu);
 
        desc_set_defaults(irq, desc, node, affinity, owner);

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