FAILED: patch "[PATCH] x86/ioapic: Force affinity setup before startup" failed to apply to 4.9-stable tree

The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 0c0e37dc11671384e53ba6ede53a4d91162a2cc5 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <[email protected]>
Date: Thu, 29 Jul 2021 23:51:49 +0200
Subject: [PATCH] x86/ioapic: Force affinity setup before startup

The IO/APIC cannot handle interrupt affinity changes safely after startup other than from an interrupt handler. The startup sequence in the generic interrupt code violates that assumption.

Mark the irq chip with the new IRQCHIP_AFFINITY_PRE_STARTUP flag so that the default interrupt setting happens before the interrupt is started up for the first time.

index d5c691a3208b..39224e035e47 100644
@@ -1986,7 +1986,8 @@ static struct irq_chip ioapic_chip __read_mostly = {
 	.irq_set_affinity	= ioapic_set_affinity,
 	.irq_retrigger		= irq_chip_retrigger_hierarchy,
 	.irq_get_irqchip_state	= ioapic_irq_get_chip_state,
-	.flags			= IRQCHIP_SKIP_SET_WAKE,
+	.flags			= IRQCHIP_SKIP_SET_WAKE |
+				  IRQCHIP_AFFINITY_PRE_STARTUP,
 };
 
 static struct irq_chip ioapic_ir_chip __read_mostly = {

@@ -1999,7 +2000,8 @@ static struct irq_chip ioapic_ir_chip __read_mostly = {
 	.irq_set_affinity	= ioapic_set_affinity,
 	.irq_retrigger		= irq_chip_retrigger_hierarchy,
 	.irq_get_irqchip_state	= ioapic_irq_get_chip_state,
-	.flags			= IRQCHIP_SKIP_SET_WAKE,
+	.flags			= IRQCHIP_SKIP_SET_WAKE |
+				  IRQCHIP_AFFINITY_PRE_STARTUP,
 };
 
 static inline void init_IO_APIC_traps(void)