ACPI fixes for 5.11-rc4

- Harden the ACPI device enumeration code against device ID length
    overflows to address a Linux VM cash on Hyper-V (Dexuan Cui).
 
  - Fix a mistake in the documentation of error type values for PCIe
    errors (Qiuxu Zhuo).
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Merge tag 'acpi-5.11-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull ACPI fixes from Rafael Wysocki:
 "These address a device ID bounds check error in the device enumeration
  code and fix a mistake in the documentation.

  Specifics:

   - Harden the ACPI device enumeration code against device ID length
     overflows to address a Linux VM cash on Hyper-V (Dexuan Cui).

   - Fix a mistake in the documentation of error type values for PCIe
     errors (Qiuxu Zhuo)"

* tag 'acpi-5.11-rc4' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  Documentation: ACPI: EINJ: Fix error type values for PCIe errors
  ACPI: scan: Harden acpi_device_add() against device ID overflows

Documentation/firmware-guide/acpi/apei/einj.rst

@@ -50,8 +50,8 @@ The following files belong to it:
   0x00000010        Memory Uncorrectable non-fatal
   0x00000020        Memory Uncorrectable fatal
   0x00000040        PCI Express Correctable
-  0x00000080        PCI Express Uncorrectable fatal
-  0x00000100        PCI Express Uncorrectable non-fatal
+  0x00000080        PCI Express Uncorrectable non-fatal
+  0x00000100        PCI Express Uncorrectable fatal
   0x00000200        Platform Correctable
   0x00000400        Platform Uncorrectable non-fatal
   0x00000800        Platform Uncorrectable fatal

drivers/acpi/internal.h

@@ -97,7 +97,7 @@ void acpi_scan_table_handler(u32 event, void *table, void *context);
 extern struct list_head acpi_bus_id_list;
 
 struct acpi_device_bus_id {
-	char bus_id[15];
+	const char *bus_id;
 	unsigned int instance_no;
 	struct list_head node;
 };

drivers/acpi/scan.c

@@ -486,6 +486,7 @@ static void acpi_device_del(struct acpi_device *device)
 				acpi_device_bus_id->instance_no--;
 			else {
 				list_del(&acpi_device_bus_id->node);
+				kfree_const(acpi_device_bus_id->bus_id);
 				kfree(acpi_device_bus_id);
 			}
 			break;
@@ -674,7 +675,14 @@ int acpi_device_add(struct acpi_device *device,
 	}
 	if (!found) {
 		acpi_device_bus_id = new_bus_id;
-		strcpy(acpi_device_bus_id->bus_id, acpi_device_hid(device));
+		acpi_device_bus_id->bus_id =
+			kstrdup_const(acpi_device_hid(device), GFP_KERNEL);
+		if (!acpi_device_bus_id->bus_id) {
+			pr_err(PREFIX "Memory allocation error for bus id\n");
+			result = -ENOMEM;
+			goto err_free_new_bus_id;
+		}
+
 		acpi_device_bus_id->instance_no = 0;
 		list_add_tail(&acpi_device_bus_id->node, &acpi_bus_id_list);
 	}
@@ -709,6 +717,11 @@ int acpi_device_add(struct acpi_device *device,
 	if (device->parent)
 		list_del(&device->node);
 	list_del(&device->wakeup_list);
+
+ err_free_new_bus_id:
+	if (!found)
+		kfree(new_bus_id);
+
 	mutex_unlock(&acpi_device_lock);
 
  err_detach: