From: Jon Derrick <jonathan.derrick@intel.com>
Date: Tue, 21 Jul 2020 14:26:09 -0600
Patch-mainline: v5.9-rc1
Subject: irqdomain/treewide: Free firmware node after domain removal
Git-commit: ec0160891e387f4771f953b888b1fe951398e5d9
References: git-fixes

Commit 711419e504eb ("irqdomain: Add the missing assignment of
domain->fwnode for named fwnode") unintentionally caused a dangling pointer
page fault issue on firmware nodes that were freed after IRQ domain
allocation. Commit e3beca48a45b fixed that dangling pointer issue by only
freeing the firmware node after an IRQ domain allocation failure. That fix
no longer frees the firmware node immediately, but leaves the firmware node
allocated after the domain is removed.

The firmware node must be kept around through irq_domain_remove, but should be
freed it afterwards.

Add the missing free operations after domain removal where where appropriate.

Fixes: e3beca48a45b ("irqdomain/treewide: Keep firmware node unconditionally allocated")
Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>	# drivers/pci
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/1595363169-7157-1-git-send-email-jonathan.derrick@intel.com
Acked-by: Olaf Hering <ohering@suse.de>
---
 arch/mips/pci/pci-xtalk-bridge.c    | 3 +++
 arch/x86/kernel/apic/io_apic.c      | 5 +++++
 drivers/iommu/intel/irq_remapping.c | 8 ++++++++
 drivers/mfd/ioc3.c                  | 6 ++++++
 drivers/pci/controller/vmd.c        | 3 +++
 5 files changed, 25 insertions(+)

--- a/arch/mips/pci/pci-xtalk-bridge.c
+++ b/arch/mips/pci/pci-xtalk-bridge.c
@@ -583,6 +583,7 @@ err_free_resource:
 	pci_free_resource_list(&host->windows);
 err_remove_domain:
 	irq_domain_remove(domain);
+	irq_domain_free_fwnode(fn);
 	return err;
 }
 
@@ -590,8 +591,10 @@ static int bridge_remove(struct platform
 {
 	struct pci_bus *bus = platform_get_drvdata(pdev);
 	struct bridge_controller *bc = BRIDGE_CONTROLLER(bus);
+	struct fwnode_handle *fn = bc->domain->fwnode;
 
 	irq_domain_remove(bc->domain);
+	irq_domain_free_fwnode(fn);
 	pci_lock_rescan_remove();
 	pci_stop_root_bus(bus);
 	pci_remove_root_bus(bus);
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -2348,8 +2348,13 @@ static int mp_irqdomain_create(int ioapi
 
 static void ioapic_destroy_irqdomain(int idx)
 {
+	struct ioapic_domain_cfg *cfg = &ioapics[idx].irqdomain_cfg;
+	struct fwnode_handle *fn = ioapics[idx].irqdomain->fwnode;
+
 	if (ioapics[idx].irqdomain) {
 		irq_domain_remove(ioapics[idx].irqdomain);
+		if (!cfg->dev)
+			irq_domain_free_fwnode(fn);
 		ioapics[idx].irqdomain = NULL;
 	}
 }
--- a/drivers/iommu/intel/irq_remapping.c
+++ b/drivers/iommu/intel/irq_remapping.c
@@ -628,13 +628,21 @@ out_free_table:
 
 static void intel_teardown_irq_remapping(struct intel_iommu *iommu)
 {
+	struct fwnode_handle *fn;
+
 	if (iommu && iommu->ir_table) {
 		if (iommu->ir_msi_domain) {
+			fn = iommu->ir_msi_domain->fwnode;
+
 			irq_domain_remove(iommu->ir_msi_domain);
+			irq_domain_free_fwnode(fn);
 			iommu->ir_msi_domain = NULL;
 		}
 		if (iommu->ir_domain) {
+			fn = iommu->ir_domain->fwnode;
+
 			irq_domain_remove(iommu->ir_domain);
+			irq_domain_free_fwnode(fn);
 			iommu->ir_domain = NULL;
 		}
 		free_pages((unsigned long)iommu->ir_table->base,
--- a/drivers/pci/controller/vmd.c
+++ b/drivers/pci/controller/vmd.c
@@ -808,6 +808,7 @@ static void vmd_cleanup_srcu(struct vmd_
 static void vmd_remove(struct pci_dev *dev)
 {
 	struct vmd_dev *vmd = pci_get_drvdata(dev);
+	struct fwnode_handle *fn = vmd->irq_domain->fwnode;
 
 	sysfs_remove_link(&vmd->dev->dev.kobj, "domain");
 	pci_stop_root_bus(vmd->bus);
@@ -666,6 +666,7 @@ static void vmd_remove(struct pci_dev *d
 	vmd_cleanup_srcu(vmd);
 	vmd_detach_resources(vmd);
 	irq_domain_remove(vmd->irq_domain);
+	irq_domain_free_fwnode(fn);
 }
 
 #ifdef CONFIG_PM_SLEEP