1 files changed, 64 insertions, 54 deletions

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 89a3ea82569b..ea0c6c2ae6f7 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -7,6 +7,8 @@
  * This file contains driver APIs to the irq subsystem.
  */
 
+#define pr_fmt(fmt) "genirq: " fmt
+
 #include <linux/irq.h>
 #include <linux/kthread.h>
 #include <linux/module.h>
@@ -14,6 +16,7 @@
 #include <linux/interrupt.h>
 #include <linux/slab.h>
 #include <linux/sched.h>
+#include <linux/task_work.h>
 
 #include "internals.h"
 
@@ -566,7 +569,7 @@ int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
                  * flow-types?
                  */
                 pr_debug("No set_type function for IRQ %d (%s)\n", irq,
-                                chip ? (chip->name ? : "unknown") : "unknown");
+                         chip ? (chip->name ? : "unknown") : "unknown");
                 return 0;
         }
 
@@ -600,7 +603,7 @@ int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
                 ret = 0;
                 break;
         default:
-                pr_err("setting trigger mode %lu for irq %u failed (%pF)\n",
+                pr_err("Setting trigger mode %lu for irq %u failed (%pF)\n",
                        flags, irq, chip->irq_set_type);
         }
         if (unmask)
@@ -773,11 +776,39 @@ static void wake_threads_waitq(struct irq_desc *desc)
                 wake_up(&desc->wait_for_threads);
 }
 
+static void irq_thread_dtor(struct task_work *unused)
+{
+        struct task_struct *tsk = current;
+        struct irq_desc *desc;
+        struct irqaction *action;
+
+        if (WARN_ON_ONCE(!(current->flags & PF_EXITING)))
+                return;
+
+        action = kthread_data(tsk);
+
+        pr_err("exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
+               tsk->comm ? tsk->comm : "", tsk->pid, action->irq);
+
+
+        desc = irq_to_desc(action->irq);
+        /*
+         * If IRQTF_RUNTHREAD is set, we need to decrement
+         * desc->threads_active and wake possible waiters.
+         */
+        if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))
+                wake_threads_waitq(desc);
+
+        /* Prevent a stale desc->threads_oneshot */
+        irq_finalize_oneshot(desc, action);
+}
+
 /*
  * Interrupt handler thread
  */
 static int irq_thread(void *data)
 {
+        struct task_work on_exit_work;
         static const struct sched_param param = {
                 .sched_priority = MAX_USER_RT_PRIO/2,
         };
@@ -793,7 +824,9 @@ static int irq_thread(void *data)
                 handler_fn = irq_thread_fn;
 
         sched_setscheduler(current, SCHED_FIFO, &param);
-        current->irq_thread = 1;
+
+        init_task_work(&on_exit_work, irq_thread_dtor, NULL);
+        task_work_add(current, &on_exit_work, false);
 
         while (!irq_wait_for_interrupt(action)) {
                 irqreturn_t action_ret;
@@ -815,45 +848,11 @@ static int irq_thread(void *data)
          * cannot touch the oneshot mask at this point anymore as
          * __setup_irq() might have given out currents thread_mask
          * again.
-         *
-         * Clear irq_thread. Otherwise exit_irq_thread() would make
-         * fuzz about an active irq thread going into nirvana.
          */
-        current->irq_thread = 0;
+        task_work_cancel(current, irq_thread_dtor);
         return 0;
 }
 
-/*
- * Called from do_exit()
- */
-void exit_irq_thread(void)
-{
-        struct task_struct *tsk = current;
-        struct irq_desc *desc;
-        struct irqaction *action;
-
-        if (!tsk->irq_thread)
-                return;
-
-        action = kthread_data(tsk);
-
-        printk(KERN_ERR
-               "exiting task \"%s\" (%d) is an active IRQ thread (irq %d)\n",
-               tsk->comm ? tsk->comm : "", tsk->pid, action->irq);
-
-        desc = irq_to_desc(action->irq);
-
-        /*
-         * If IRQTF_RUNTHREAD is set, we need to decrement
-         * desc->threads_active and wake possible waiters.
-         */
-        if (test_and_clear_bit(IRQTF_RUNTHREAD, &action->thread_flags))
-                wake_threads_waitq(desc);
-
-        /* Prevent a stale desc->threads_oneshot */
-        irq_finalize_oneshot(desc, action);
-}
-
 static void irq_setup_forced_threading(struct irqaction *new)
 {
         if (!force_irqthreads)
@@ -878,7 +877,6 @@ static int
 __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
 {
         struct irqaction *old, **old_ptr;
-        const char *old_name = NULL;
         unsigned long flags, thread_mask = 0;
         int ret, nested, shared = 0;
         cpumask_var_t mask;
@@ -972,10 +970,8 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
                  */
                 if (!((old->flags & new->flags) & IRQF_SHARED) ||
                     ((old->flags ^ new->flags) & IRQF_TRIGGER_MASK) ||
-                    ((old->flags ^ new->flags) & IRQF_ONESHOT)) {
-                        old_name = old->name;
+                    ((old->flags ^ new->flags) & IRQF_ONESHOT))
                         goto mismatch;
-                }
 
                 /* All handlers must agree on per-cpuness */
                 if ((old->flags & IRQF_PERCPU) !=
@@ -1031,6 +1027,27 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
                  * all existing action->thread_mask bits.
                  */
                 new->thread_mask = 1 << ffz(thread_mask);
+
+        } else if (new->handler == irq_default_primary_handler) {
+                /*
+                 * The interrupt was requested with handler = NULL, so
+                 * we use the default primary handler for it. But it
+                 * does not have the oneshot flag set. In combination
+                 * with level interrupts this is deadly, because the
+                 * default primary handler just wakes the thread, then
+                 * the irq lines is reenabled, but the device still
+                 * has the level irq asserted. Rinse and repeat....
+                 *
+                 * While this works for edge type interrupts, we play
+                 * it safe and reject unconditionally because we can't
+                 * say for sure which type this interrupt really
+                 * has. The type flags are unreliable as the
+                 * underlying chip implementation can override them.
+                 */
+                pr_err("Threaded irq requested with handler=NULL and !ONESHOT for irq %d\n",
+                       irq);
+                ret = -EINVAL;
+                goto out_mask;
         }
 
         if (!shared) {
@@ -1078,7 +1095,7 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
 
                 if (nmsk != omsk)
                         /* hope the handler works with current  trigger mode */
-                        pr_warning("IRQ %d uses trigger mode %u; requested %u\n",
+                        pr_warning("irq %d uses trigger mode %u; requested %u\n",
                                    irq, nmsk, omsk);
         }
 
@@ -1115,14 +1132,13 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new)
         return 0;
 
 mismatch:
-#ifdef CONFIG_DEBUG_SHIRQ
         if (!(new->flags & IRQF_PROBE_SHARED)) {
-                printk(KERN_ERR "IRQ handler type mismatch for IRQ %d\n", irq);
-                if (old_name)
-                        printk(KERN_ERR "current handler: %s\n", old_name);
+                pr_err("Flags mismatch irq %d. %08x (%s) vs. %08x (%s)\n",
+                       irq, new->flags, new->name, old->flags, old->name);
+#ifdef CONFIG_DEBUG_SHIRQ
                 dump_stack();
-        }
 #endif
+        }
         ret = -EBUSY;
 
 out_mask:
@@ -1204,12 +1220,6 @@ static struct irqaction *__free_irq(unsigned int irq, void *dev_id)
         /* Found it - now remove it from the list of entries: */
         *action_ptr = action->next;
 
-        /* Currently used only by UML, might disappear one day: */
-#ifdef CONFIG_IRQ_RELEASE_METHOD
-        if (desc->irq_data.chip->release)
-                desc->irq_data.chip->release(irq, dev_id);
-#endif
-
         /* If this was the last handler, shut down the IRQ line: */
         if (!desc->action)
                 irq_shutdown(desc);