2 files changed, 40 insertions, 9 deletions

diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index d70394f12ee9..71eba24a39a2 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -359,6 +359,23 @@ static inline void mask_ack_irq(struct irq_desc *desc, int irq)
                 if (desc->chip->ack)
                         desc->chip->ack(irq);
         }
+        desc->status |= IRQ_MASKED;
+}
+
+static inline void mask_irq(struct irq_desc *desc, int irq)
+{
+        if (desc->chip->mask) {
+                desc->chip->mask(irq);
+                desc->status |= IRQ_MASKED;
+        }
+}
+
+static inline void unmask_irq(struct irq_desc *desc, int irq)
+{
+        if (desc->chip->unmask) {
+                desc->chip->unmask(irq);
+                desc->status &= ~IRQ_MASKED;
+        }
 }
 
 /*
@@ -484,10 +501,8 @@ handle_level_irq(unsigned int irq, struct irq_desc *desc)
         raw_spin_lock(&desc->lock);
         desc->status &= ~IRQ_INPROGRESS;
 
-        if (unlikely(desc->status & IRQ_ONESHOT))
-                desc->status |= IRQ_MASKED;
-        else if (!(desc->status & IRQ_DISABLED) && desc->chip->unmask)
-                desc->chip->unmask(irq);
+        if (!(desc->status & (IRQ_DISABLED | IRQ_ONESHOT)))
+                unmask_irq(desc, irq);
 out_unlock:
         raw_spin_unlock(&desc->lock);
 }
@@ -524,8 +539,7 @@ handle_fasteoi_irq(unsigned int irq, struct irq_desc *desc)
         action = desc->action;
         if (unlikely(!action || (desc->status & IRQ_DISABLED))) {
                 desc->status |= IRQ_PENDING;
-                if (desc->chip->mask)
-                        desc->chip->mask(irq);
+                mask_irq(desc, irq);
                 goto out;
         }
 
@@ -593,7 +607,7 @@ handle_edge_irq(unsigned int irq, struct irq_desc *desc)
                 irqreturn_t action_ret;
 
                 if (unlikely(!action)) {
-                        desc->chip->mask(irq);
+                        mask_irq(desc, irq);
                         goto out_unlock;
                 }
 
@@ -605,8 +619,7 @@ handle_edge_irq(unsigned int irq, struct irq_desc *desc)
                 if (unlikely((desc->status &
                                (IRQ_PENDING | IRQ_MASKED | IRQ_DISABLED)) ==
                               (IRQ_PENDING | IRQ_MASKED))) {
-                        desc->chip->unmask(irq);
-                        desc->status &= ~IRQ_MASKED;
+                        unmask_irq(desc, irq);
                 }
 
                 desc->status &= ~IRQ_PENDING;
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index eb6078ca60c7..69a3d7b9414c 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -483,8 +483,26 @@ static int irq_wait_for_interrupt(struct irqaction *action)
  */
 static void irq_finalize_oneshot(unsigned int irq, struct irq_desc *desc)
 {
+again:
         chip_bus_lock(irq, desc);
         raw_spin_lock_irq(&desc->lock);
+
+        /*
+         * Implausible though it may be we need to protect us against
+         * the following scenario:
+         *
+         * The thread is faster done than the hard interrupt handler
+         * on the other CPU. If we unmask the irq line then the
+         * interrupt can come in again and masks the line, leaves due
+         * to IRQ_INPROGRESS and the irq line is masked forever.
+         */
+        if (unlikely(desc->status & IRQ_INPROGRESS)) {
+                raw_spin_unlock_irq(&desc->lock);
+                chip_bus_sync_unlock(irq, desc);
+                cpu_relax();
+                goto again;
+        }
+
         if (!(desc->status & IRQ_DISABLED) && (desc->status & IRQ_MASKED)) {
                 desc->status &= ~IRQ_MASKED;
                 desc->chip->unmask(irq);