Commit 3a75f9f2 authored by Ard Biesheuvel's avatar Ard Biesheuvel
Browse files

efi: vars: Use locking version to iterate over efivars linked lists 



Both efivars and efivarfs uses __efivar_entry_iter() to go over the
linked list that shadows the list of EFI variables held by the firmware,
but fail to call the begin/end helpers that are documented as a
prerequisite.

So switch to the proper version, which is efivar_entry_iter(). Given
that in both cases, efivar_entry_remove() is invoked with the lock held
already, don't take the lock there anymore.

Signed-off-by: default avatarArd Biesheuvel <ardb@kernel.org>
parent 85974825

drivers/firmware/efi/efivars.c

+2 −6
Original line number Diff line number Diff line
@@ -602,10 +602,7 @@ static int efivars_sysfs_callback(efi_char16_t *name, efi_guid_t vendor, 


static int efivar_sysfs_destroy(struct efivar_entry *entry, void *data)

{

	int err = efivar_entry_remove(entry);



	if (err)

		return err;

	efivar_entry_remove(entry);

	efivar_unregister(entry);

	return 0;

}
@@ -615,8 +612,7 @@ static void efivars_sysfs_exit(void) 
	/* Remove all entries and destroy */

	int err;



	err = __efivar_entry_iter(efivar_sysfs_destroy, &efivar_sysfs_list,

				  NULL, NULL);

	err = efivar_entry_iter(efivar_sysfs_destroy, &efivar_sysfs_list, NULL);

	if (err) {

		pr_err("efivars: Failed to destroy sysfs entries\n");

		return;

drivers/firmware/efi/vars.c

+1 −8
Original line number Diff line number Diff line
@@ -523,17 +523,10 @@ EXPORT_SYMBOL_GPL(__efivar_entry_add); 
/**

 * efivar_entry_remove - remove entry from variable list

 * @entry: entry to remove from list

 *

 * Returns 0 on success, or a kernel error code on failure.

 */

int efivar_entry_remove(struct efivar_entry *entry)

void efivar_entry_remove(struct efivar_entry *entry)

{

	if (down_interruptible(&efivars_lock))

		return -EINTR;

	list_del(&entry->list);

	up(&efivars_lock);



	return 0;

}

EXPORT_SYMBOL_GPL(efivar_entry_remove);

fs/efivarfs/super.c

+3 −6
Original line number Diff line number Diff line
@@ -180,10 +180,7 @@ static int efivarfs_callback(efi_char16_t *name16, efi_guid_t vendor, 


static int efivarfs_destroy(struct efivar_entry *entry, void *data)

{

	int err = efivar_entry_remove(entry);



	if (err)

		return err;

	efivar_entry_remove(entry);

	kfree(entry);

	return 0;

}
@@ -219,7 +216,7 @@ static int efivarfs_fill_super(struct super_block *sb, struct fs_context *fc) 


	err = efivar_init(efivarfs_callback, (void *)sb, true, &efivarfs_list);

	if (err)

		__efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL, NULL);

		efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL);



	return err;

}
@@ -244,7 +241,7 @@ static void efivarfs_kill_sb(struct super_block *sb) 
	kill_litter_super(sb);



	/* Remove all entries and destroy */

	__efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL, NULL);

	efivar_entry_iter(efivarfs_destroy, &efivarfs_list, NULL);

}



static struct file_system_type efivarfs_type = {

include/linux/efi.h

+1 −1
Original line number Diff line number Diff line
@@ -1063,7 +1063,7 @@ int efivar_init(int (*func)(efi_char16_t *, efi_guid_t, unsigned long, void *), 


int efivar_entry_add(struct efivar_entry *entry, struct list_head *head);

void __efivar_entry_add(struct efivar_entry *entry, struct list_head *head);

int efivar_entry_remove(struct efivar_entry *entry);

void efivar_entry_remove(struct efivar_entry *entry);



int __efivar_entry_delete(struct efivar_entry *entry);

int efivar_entry_delete(struct efivar_entry *entry);