Revert "efi: random: refresh non-volatile random seed when RNG is initialized"

This reverts commit e7b813b32a42a3a6281a4fd9ae7700a0257c1d50 (and the
subsequent fix for it: 41a15855c1ee "efi: random: fix NULL-deref when
refreshing seed").

It turns otu to cause non-deterministic boot stalls on at least a HP
6730b laptop.

Reported-and-bisected-by: Sami Korkalainen <sami.korkalainen@proton.me>
Link: https://lore.kernel.org/all/GQUnKz2al3yke5mB2i1kp3SzNHjK8vi6KJEh7rnLrOQ24OrlljeCyeWveLW9pICEmB9Qc8PKdNt3w1t_g3-Uvxq1l8Wj67PpoMeWDoH8PKk=@proton.me/
Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/firmware/efi/efi.c b/drivers/firmware/efi/efi.c
index abeff7d..34b9e78 100644 (file)
--- a/drivers/firmware/efi/efi.c
+++ b/drivers/firmware/efi/efi.c
@@ -361,24 +361,6 @@ static void __init efi_debugfs_init(void)
 static inline void efi_debugfs_init(void) {}
 #endif
 
-static void refresh_nv_rng_seed(struct work_struct *work)
-{
-       u8 seed[EFI_RANDOM_SEED_SIZE];
-
-       get_random_bytes(seed, sizeof(seed));
-       efi.set_variable(L"RandomSeed", &LINUX_EFI_RANDOM_SEED_TABLE_GUID,
-                        EFI_VARIABLE_NON_VOLATILE | EFI_VARIABLE_BOOTSERVICE_ACCESS |
-                        EFI_VARIABLE_RUNTIME_ACCESS, sizeof(seed), seed);
-       memzero_explicit(seed, sizeof(seed));
-}
-static int refresh_nv_rng_seed_notification(struct notifier_block *nb, unsigned long action, void *data)
-{
-       static DECLARE_WORK(work, refresh_nv_rng_seed);
-       schedule_work(&work);
-       return NOTIFY_DONE;
-}
-static struct notifier_block refresh_nv_rng_seed_nb = { .notifier_call = refresh_nv_rng_seed_notification };
-
 /*
  * We register the efi subsystem with the firmware subsystem and the
  * efivars subsystem with the efi subsystem, if the system was booted with
@@ -451,9 +433,6 @@ static int __init efisubsys_init(void)
                platform_device_register_simple("efi_secret", 0, NULL, 0);
 #endif
 
-       if (efi_rt_services_supported(EFI_RT_SUPPORTED_SET_VARIABLE))
-               execute_with_initialized_rng(&refresh_nv_rng_seed_nb);
-
        return 0;
 
 err_remove_group: