Patch "iommu/vt-d: Use BUS_NOTIFY_REMOVED_DEVICE in hotplug path" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

iommu/vt-d: Use BUS_NOTIFY_REMOVED_DEVICE in hotplug path

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
iommu-vt-d-use-bus_notify_removed_device-in-hotplug-path.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Joerg Roedel <[email protected]>
Date: Mon, 29 Feb 2016 23:49:47 +0100
Subject: iommu/vt-d: Use BUS_NOTIFY_REMOVED_DEVICE in hotplug path

From: Joerg Roedel <[email protected]>

commit e6a8c9b337eed56eb481e1b4dd2180c25a1e5310 upstream.

In the PCI hotplug path of the Intel IOMMU driver, replace the usage of the BUS_NOTIFY_DEL_DEVICE notifier, which is executed before the driver is unbound from the device, with BUS_NOTIFY_REMOVED_DEVICE, which runs after that.

This fixes a kernel BUG being triggered in the VT-d code when the device driver tries to unmap DMA buffers and the VT-d driver already destroyed all mappings.

---
 drivers/iommu/dmar.c        |    5 +++--
 drivers/iommu/intel-iommu.c |    4 ++--
 2 files changed, 5 insertions(+), 4 deletions(-)

@@ -329,7 +329,8 @@ static int dmar_pci_bus_notifier(struct
 	/* Only care about add/remove events for physical functions */
 	if (pdev->is_virtfn)
 		return NOTIFY_DONE;
-	if (action != BUS_NOTIFY_ADD_DEVICE && action != BUS_NOTIFY_DEL_DEVICE)
+	if (action != BUS_NOTIFY_ADD_DEVICE &&
+	    action != BUS_NOTIFY_REMOVED_DEVICE)
 		return NOTIFY_DONE;
 
 	info = dmar_alloc_pci_notify_info(pdev, action);

@@ -339,7 +340,7 @@ static int dmar_pci_bus_notifier(struct
 	down_write(&dmar_global_lock);
 	if (action == BUS_NOTIFY_ADD_DEVICE)
 		dmar_pci_bus_add_dev(info);
-	else if (action == BUS_NOTIFY_DEL_DEVICE)
+	else if (action == BUS_NOTIFY_REMOVED_DEVICE)
 		dmar_pci_bus_del_dev(info);
 	up_write(&dmar_global_lock);
 

@@ -4367,7 +4367,7 @@ int dmar_iommu_notify_scope_dev(struct d
 				rmrru->devices_cnt);
 			if(ret < 0)
 				return ret;
-		} else if (info->event == BUS_NOTIFY_DEL_DEVICE) {
+		} else if (info->event == BUS_NOTIFY_REMOVED_DEVICE) {
 			dmar_remove_dev_scope(info, rmrr->segment,
 				rmrru->devices, rmrru->devices_cnt);
 		}

@@ -4387,7 +4387,7 @@ int dmar_iommu_notify_scope_dev(struct d
 				break;
 			else if(ret < 0)
 				return ret;
-		} else if (info->event == BUS_NOTIFY_DEL_DEVICE) {
+		} else if (info->event == BUS_NOTIFY_REMOVED_DEVICE) {
 			if (dmar_remove_dev_scope(info, atsr->segment,
 					atsru->devices, atsru->devices_cnt))
 				break;

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/iommu-vt-d-use-bus_notify_removed_device-in-hotplug-path.patch queue-4.4/iommu-amd-fix-boot-warning-when-device-00-00.0-is-not-iommu-covered.patch queue-4.4/iommu-amd-apply-workaround-for-ats-write-permission-check.patch