efi: fix error handling in add_sysfs_runtime_map_entry()

I spotted two (difficult to hit) bugs while reviewing this.

1) There is a double free bug because we unregister "map_kset" in add_sysfs_runtime_map_entry() and also efi_runtime_map_init().
2) If we fail to allocate "entry" then we should return ERR_PTR(-ENOMEM) instead of NULL.

Signed-off-by Dan Carpenter <[email protected]>

drivers/firmware/efi/runtime-map.c +3 -4

index 87b8e3b..5c55227 100644
@@ -120,7 +120,8 @@ add_sysfs_runtime_map_entry(struct kobject *kobj, int nr)
 	entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 	if (!entry) {
 		kset_unregister(map_kset);
-		return entry;
+		map_kset = NULL;
+		return ERR_PTR(-ENOMEM);
 	}
 
 	memcpy(&entry->md, efi_runtime_map + nr * efi_memdesc_size,

@@ -132,6 +133,7 @@ add_sysfs_runtime_map_entry(struct kobject *kobj, int nr)
 	if (ret) {
 		kobject_put(&entry->kobj);
 		kset_unregister(map_kset);
+		map_kset = NULL;
 		return ERR_PTR(ret);
 	}
 

@@ -195,8 +197,6 @@ out_add_entry:
 		entry = *(map_entries + j);
 		kobject_put(&entry->kobj);
 	}
-	if (map_kset)
-		kset_unregister(map_kset);
 out:
 	return ret;
 }
--

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