linux-kernel - [PATCH 5.18 866/879] Revert "random: use static branch for crng

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20220607165027.989427675@linuxfoundation.org>
Date:   Tue,  7 Jun 2022 19:06:24 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, "Jason A. Donenfeld" <Jason@...c4.com>
Subject: [PATCH 5.18 866/879] Revert "random: use static branch for crng_ready()"

From: "Jason A. Donenfeld" <Jason@...c4.com>

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@...c4.com>
---
 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);