[PATCH] Fix race in efi variable delete code.

Fix race when deleting an EFI variable and issuing another EFI command on the
same variable. The removal of the variable from the efivars_list should be
done in efivar_delete and not delayed until the kprobes release.

Signed-off-by: Prarit Bhargava <prarit@xxxxxxxxxx>

diff --git a/drivers/firmware/efivars.c b/drivers/firmware/efivars.c
index 5ab5e39..bf2ca97 100644
--- a/drivers/firmware/efivars.c
+++ b/drivers/firmware/efivars.c
@@ -385,10 +385,8 @@ static struct sysfs_ops efivar_attr_ops = {

static void efivar_release(struct kobject *kobj)
{
- struct efivar_entry *var = container_of(kobj, struct efivar_entry, kobj);
- spin_lock(&efivars_lock);
- list_del(&var->list);
- spin_unlock(&efivars_lock);
+ struct efivar_entry *var = container_of(kobj, struct efivar_entry,
+ kobj);
kfree(var);
}

@@ -537,6 +535,9 @@ efivar_delete(struct subsystem *sub, const char *buf, size_t count)
spin_unlock(&efivars_lock);
return -EIO;
}
+
+ list_del(&search_efivar->list);
+
/* We need to release this lock before unregistering. */
spin_unlock(&efivars_lock);

-
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