RE: "No irq handler for vector" problem

[Thomas Gleixner <tglx@xxxxxxxxxxxxx>]

Michael,

On Sun, 23 Jun 2019, Michael Shych wrote:
> 
> > -----Original Message-----
> > From: Hodaszi, Robert <Robert.Hodaszi@xxxxxxxx>
> > Sent: Friday, June 21, 2019 8:47 PM
> > To: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> > Cc: Michael Shych <michaelsh@xxxxxxxxxxxx>; x86@xxxxxxxxxx; Vadim
> > Pasternak <vadimp@xxxxxxxxxxxx>; Ido Schimmel
> > <idosch@xxxxxxxxxxxx>; Greg Kroah-Hartman
> > <gregkh@xxxxxxxxxxxxxxxxxxx>; linux-serial@xxxxxxxxxxxxxxx
> > Subject: RE: "No irq handler for vector" problem

can you please teach your mail client not to copy the full header into the
reply. That's really not useful on a mailing list.

> > On June 21, 2019 19:00:25 Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
> > >
> > > Not freeing the vector would just paper over the problem. Can you try the
> > > patch below?
> > >
> 
> Tried patch on our system. The problem still exist:
>  [   49.802818] do_IRQ: 0.37 No irq handler for vector

Stared some more into the interrupt code. I think Robert was on the right
track, but I did not see the tree in the forest.

The scenario he described can actually happen and yes, we should deactivate
the interrupt after the synchronize_hardirq() and not before. Tentative fix
below.

Thanks,

	tglx

8<-------------
--- a/kernel/irq/autoprobe.c
+++ b/kernel/irq/autoprobe.c
@@ -90,7 +90,7 @@ unsigned long probe_irq_on(void)
 			/* It triggered already - consider it spurious. */
 			if (!(desc->istate & IRQS_WAITING)) {
 				desc->istate &= ~IRQS_AUTODETECT;
-				irq_shutdown(desc);
+				irq_shutdown_and_deactivate(desc);
 			} else
 				if (i < 32)
 					mask |= 1 << i;
@@ -127,7 +127,7 @@ unsigned int probe_irq_mask(unsigned lon
 				mask |= 1 << i;
 
 			desc->istate &= ~IRQS_AUTODETECT;
-			irq_shutdown(desc);
+			irq_shutdown_and_deactivate(desc);
 		}
 		raw_spin_unlock_irq(&desc->lock);
 	}
@@ -169,7 +169,7 @@ int probe_irq_off(unsigned long val)
 				nr_of_irqs++;
 			}
 			desc->istate &= ~IRQS_AUTODETECT;
-			irq_shutdown(desc);
+			irq_shutdown_and_deactivate(desc);
 		}
 		raw_spin_unlock_irq(&desc->lock);
 	}
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -314,6 +314,12 @@ void irq_shutdown(struct irq_desc *desc)
 		}
 		irq_state_clr_started(desc);
 	}
+}
+
+
+void irq_shutdown_and_deactivate(struct irq_desc *desc)
+{
+	irq_shutdown(desc);
 	/*
 	 * This must be called even if the interrupt was never started up,
 	 * because the activation can happen before the interrupt is
--- a/kernel/irq/cpuhotplug.c
+++ b/kernel/irq/cpuhotplug.c
@@ -116,7 +116,7 @@ static bool migrate_one_irq(struct irq_d
 		 */
 		if (irqd_affinity_is_managed(d)) {
 			irqd_set_managed_shutdown(d);
-			irq_shutdown(desc);
+			irq_shutdown_and_deactivate(desc);
 			return false;
 		}
 		affinity = cpu_online_mask;
--- a/kernel/irq/internals.h
+++ b/kernel/irq/internals.h
@@ -82,6 +82,7 @@ extern int irq_activate_and_startup(stru
 extern int irq_startup(struct irq_desc *desc, bool resend, bool force);
 
 extern void irq_shutdown(struct irq_desc *desc);
+extern void irq_shutdown_and_deactivate(struct irq_desc *desc);
 extern void irq_enable(struct irq_desc *desc);
 extern void irq_disable(struct irq_desc *desc);
 extern void irq_percpu_enable(struct irq_desc *desc, unsigned int cpu);
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -13,6 +13,7 @@
 #include <linux/module.h>
 #include <linux/random.h>
 #include <linux/interrupt.h>
+#include <linux/irqdomain.h>
 #include <linux/slab.h>
 #include <linux/sched.h>
 #include <linux/sched/rt.h>
@@ -1699,6 +1700,7 @@ static struct irqaction *__free_irq(stru
 	/* If this was the last handler, shut down the IRQ line: */
 	if (!desc->action) {
 		irq_settings_clr_disable_unlazy(desc);
+		/* Only shutdown. Deactivate after synchronize_irq() */
 		irq_shutdown(desc);
 	}
 
@@ -1768,6 +1770,14 @@ static struct irqaction *__free_irq(stru
 		 * require it to deallocate resources over the slow bus.
 		 */
 		chip_bus_lock(desc);
+		/*
+		 * There is no interrupt on the fly anymore. Deactivate it
+		 * completely.
+		 */
+		raw_spin_lock_irqsave(&desc->lock, flags);
+		irq_domain_deactivate_irq(&desc->irq_data);
+		raw_spin_unlock_irqrestore(&desc->lock, flags);
+
 		irq_release_resources(desc);
 		chip_bus_sync_unlock(desc);
 		irq_remove_timings(desc);
@@ -1855,7 +1865,7 @@ static const void *__cleanup_nmi(unsigne
 	}
 
 	irq_settings_clr_disable_unlazy(desc);
-	irq_shutdown(desc);
+	irq_shutdown_and_deactivate(desc);
 
 	irq_release_resources(desc);