This is a note to let you know that I've just added the patch titled Revert "random: use static branch for crng_ready()" to the 5.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: revert-random-use-static-branch-for-crng_ready.patch and it can be found in the queue-5.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From Jason@xxxxxxxxx Tue Jun 7 11:12:02 2022 From: "Jason A. Donenfeld" <Jason@xxxxxxxxx> Date: Tue, 7 Jun 2022 10:40:05 +0200 Subject: Revert "random: use static branch for crng_ready()" To: stable@xxxxxxxxxxxxxxx, gregkh@xxxxxxxxxxxxxxxxxxx Cc: "Jason A. Donenfeld" <Jason@xxxxxxxxx> Message-ID: <20220607084005.666059-1-Jason@xxxxxxxxx> From: "Jason A. Donenfeld" <Jason@xxxxxxxxx> This reverts upstream commit f5bda35fba615ace70a656d4700423fa6c9bebee from stable. It's not essential and will take some time during 5.19 to work out properly. Signed-off-by: Jason A. Donenfeld <Jason@xxxxxxxxx> --- drivers/char/random.c | 12 ++---------- 1 file changed, 2 insertions(+), 10 deletions(-) --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -78,8 +78,7 @@ static enum { CRNG_EARLY = 1, /* At least POOL_EARLY_BITS collected */ CRNG_READY = 2 /* Fully initialized with POOL_READY_BITS collected */ } crng_init __read_mostly = CRNG_EMPTY; -static DEFINE_STATIC_KEY_FALSE(crng_is_ready); -#define crng_ready() (static_branch_likely(&crng_is_ready) || crng_init >= CRNG_READY) +#define crng_ready() (likely(crng_init >= CRNG_READY)) /* Various types of waiters for crng_init->CRNG_READY transition. */ static DECLARE_WAIT_QUEUE_HEAD(crng_init_wait); static struct fasync_struct *fasync; @@ -109,11 +108,6 @@ bool rng_is_initialized(void) } EXPORT_SYMBOL(rng_is_initialized); -static void __cold crng_set_ready(struct work_struct *work) -{ - static_branch_enable(&crng_is_ready); -} - /* Used by wait_for_random_bytes(), and considered an entropy collector, below. */ static void try_to_generate_entropy(void); @@ -267,7 +261,7 @@ static void crng_reseed(void) ++next_gen; WRITE_ONCE(base_crng.generation, next_gen); WRITE_ONCE(base_crng.birth, jiffies); - if (!static_branch_likely(&crng_is_ready)) + if (!crng_ready()) crng_init = CRNG_READY; spin_unlock_irqrestore(&base_crng.lock, flags); memzero_explicit(key, sizeof(key)); @@ -710,7 +704,6 @@ static void extract_entropy(void *buf, s static void __cold _credit_init_bits(size_t bits) { - static struct execute_work set_ready; unsigned int new, orig, add; unsigned long flags; @@ -726,7 +719,6 @@ static void __cold _credit_init_bits(siz if (orig < POOL_READY_BITS && new >= POOL_READY_BITS) { crng_reseed(); /* Sets crng_init to CRNG_READY under base_crng.lock. */ - execute_in_process_context(crng_set_ready, &set_ready); process_random_ready_list(); wake_up_interruptible(&crng_init_wait); kill_fasync(&fasync, SIGIO, POLL_IN); Patches currently in stable-queue which might be from Jason@xxxxxxxxx are queue-5.18/arm64-initialize-jump-labels-before-setup_machine_fdt.patch queue-5.18/openrisc-start-cpu-timer-early-in-boot.patch queue-5.18/revert-random-use-static-branch-for-crng_ready.patch