aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
-rw-r--r--drivers/firmware/efivars.c49
1 files changed, 48 insertions, 1 deletions
diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c
index cc4e4b21108..0b66b93cf7a 100644
--- a/drivers/firmware/efivars.c
+++ b/drivers/firmware/efivars.c
@@ -159,6 +159,7 @@ efivar_create_sysfs_entry(struct efivars *efivars,
static void efivar_update_sysfs_entries(struct work_struct *);
static DECLARE_WORK(efivar_work, efivar_update_sysfs_entries);
+static bool efivar_wq_enabled = true;
/* Return the number of unicode characters in data */
static unsigned long
@@ -842,7 +843,8 @@ static int efi_pstore_write(enum pstore_type_id type, u64 *id,
if (found)
efivar_unregister(found);
- schedule_work(&efivar_work);
+ if (efivar_wq_enabled)
+ schedule_work(&efivar_work);
*id = part;
return ret;
@@ -1305,6 +1307,35 @@ void unregister_efivars(struct efivars *efivars)
}
EXPORT_SYMBOL_GPL(unregister_efivars);
+/*
+ * Print a warning when duplicate EFI variables are encountered and
+ * disable the sysfs workqueue since the firmware is buggy.
+ */
+static void dup_variable_bug(efi_char16_t *s16, efi_guid_t *vendor_guid,
+ unsigned long len16)
+{
+ size_t i, len8 = len16 / sizeof(efi_char16_t);
+ char *s8;
+
+ /*
+ * Disable the workqueue since the algorithm it uses for
+ * detecting new variables won't work with this buggy
+ * implementation of GetNextVariableName().
+ */
+ efivar_wq_enabled = false;
+
+ s8 = kzalloc(len8, GFP_KERNEL);
+ if (!s8)
+ return;
+
+ for (i = 0; i < len8; i++)
+ s8[i] = s16[i];
+
+ printk(KERN_WARNING "efivars: duplicate variable: %s-%pUl\n",
+ s8, vendor_guid);
+ kfree(s8);
+}
+
int register_efivars(struct efivars *efivars,
const struct efivar_operations *ops,
struct kobject *parent_kobj)
@@ -1347,6 +1378,22 @@ int register_efivars(struct efivars *efivars,
case EFI_SUCCESS:
variable_name_size = var_name_strnsize(variable_name,
variable_name_size);
+
+ /*
+ * Some firmware implementations return the
+ * same variable name on multiple calls to
+ * get_next_variable(). Terminate the loop
+ * immediately as there is no guarantee that
+ * we'll ever see a different variable name,
+ * and may end up looping here forever.
+ */
+ if (variable_is_present(variable_name, &vendor_guid)) {
+ dup_variable_bug(variable_name, &vendor_guid,
+ variable_name_size);
+ status = EFI_NOT_FOUND;
+ break;
+ }
+
efivar_create_sysfs_entry(efivars,
variable_name_size,
variable_name,