x86, irq: Plug memory leak in sparse irq

free_irq_cfg() is not freeing the cpumask_vars in irq_cfg. Fixing this
triggers a use after free caused by the fact that copying struct
irq_cfg is done with memcpy, which copies the pointer not the cpumask.

Fix both places.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Yinghai Lu <yhlu.kernel@gmail.com>
LKML-Reference: <alpine.LFD.2.00.1009282052570.2416@localhost6.localdomain6>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@kernel.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

arch/x86/kernel/apic/io_apic.c

@@ -306,14 +306,19 @@ void arch_init_copy_chip_data(struct irq_desc *old_desc,
 
 	old_cfg = old_desc->chip_data;
 
-	memcpy(cfg, old_cfg, sizeof(struct irq_cfg));
+	cfg->vector = old_cfg->vector;
+	cfg->move_in_progress = old_cfg->move_in_progress;
+	cpumask_copy(cfg->domain, old_cfg->domain);
+	cpumask_copy(cfg->old_domain, old_cfg->old_domain);
 
 	init_copy_irq_2_pin(old_cfg, cfg, node);
 }
 
-static void free_irq_cfg(struct irq_cfg *old_cfg)
+static void free_irq_cfg(struct irq_cfg *cfg)
 {
-	kfree(old_cfg);
+	free_cpumask_var(cfg->domain);
+	free_cpumask_var(cfg->old_domain);
+	kfree(cfg);
 }
 
 void arch_free_chip_data(struct irq_desc *old_desc, struct irq_desc *desc)