diff options
authorMatt Fleming <>2013-04-26 10:10:55 +0100
committerLinus Torvalds <>2013-04-26 08:02:03 -0700
commitf464246d85d5a5c0fdbf5838b8c58ef59bd82fcc (patch)
parent37b7f3c76595e23257f61bd80b223de8658617ee (diff)
efivars: only check for duplicates on the registered list
variable_is_present() accesses '__efivars' directly, but when called via gsmi_init() Michel reports observing the following crash, BUG: unable to handle kernel NULL pointer dereference at (null) IP: variable_is_present+0x55/0x170 Call Trace: register_efivars+0x106/0x370 gsmi_init+0x2ad/0x3da do_one_initcall+0x3f/0x170 The reason for the crash is that '__efivars' hasn't been initialised nor has it been registered with register_efivars() by the time the google EFI SMI driver runs. The gsmi code uses its own struct efivars, and therefore, a different variable list. Fix the above crash by passing the registered struct efivars to variable_is_present(), so that we traverse the correct list. Reported-by: Michel Lespinasse <> Tested-by: Michel Lespinasse <> Cc: Mike Waychison <> Cc: Matthew Garrett <> Cc: Seiji Aguchi <> Signed-off-by: Matt Fleming <> Signed-off-by: Linus Torvalds <>
1 files changed, 7 insertions, 5 deletions
diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c
index 182ce947117..f4baa11d364 100644
--- a/drivers/firmware/efivars.c
+++ b/drivers/firmware/efivars.c
@@ -1628,10 +1628,11 @@ static ssize_t efivar_delete(struct file *filp, struct kobject *kobj,
return count;
-static bool variable_is_present(efi_char16_t *variable_name, efi_guid_t *vendor)
+static bool variable_is_present(struct efivars *efivars,
+ efi_char16_t *variable_name,
+ efi_guid_t *vendor)
struct efivar_entry *entry, *n;
- struct efivars *efivars = &__efivars;
unsigned long strsize1, strsize2;
bool found = false;
@@ -1703,8 +1704,8 @@ static void efivar_update_sysfs_entries(struct work_struct *work)
if (status != EFI_SUCCESS) {
} else {
- if (!variable_is_present(variable_name,
- &vendor)) {
+ if (!variable_is_present(efivars,
+ variable_name, &vendor)) {
found = true;
@@ -2008,7 +2009,8 @@ int register_efivars(struct efivars *efivars,
* we'll ever see a different variable name,
* and may end up looping here forever.
- if (variable_is_present(variable_name, &vendor_guid)) {
+ if (variable_is_present(efivars, variable_name,
+ &vendor_guid)) {
dup_variable_bug(variable_name, &vendor_guid,
status = EFI_NOT_FOUND;