This is a note to let you know that I've just added the patch titled
random: quiet urandom warning ratelimit suppression message
to the 5.4-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:
random-quiet-urandom-warning-ratelimit-suppression-message.patch
and it can be found in the queue-5.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From c01d4d0a82b71857be7449380338bc53dde2da92 Mon Sep 17 00:00:00 2001
From: "Jason A. Donenfeld" <Jason@xxxxxxxxx>
Date: Thu, 16 Jun 2022 15:00:51 +0200
Subject: random: quiet urandom warning ratelimit suppression message
From: Jason A. Donenfeld <Jason@xxxxxxxxx>
commit c01d4d0a82b71857be7449380338bc53dde2da92 upstream.
random.c ratelimits how much it warns about uninitialized urandom reads
using __ratelimit(). When the RNG is finally initialized, it prints the
number of missed messages due to ratelimiting.
It has been this way since that functionality was introduced back in
2018. Recently, cc1e127bfa95 ("random: remove ratelimiting for in-kernel
unseeded randomness") put a bit more stress on the urandom ratelimiting,
which teased out a bug in the implementation.
Specifically, when under pressure, __ratelimit() will print its own
message and reset the count back to 0, making the final message at the
end less useful. Secondly, it does so as a pr_warn(), which apparently
is undesirable for people's CI.
Fortunately, __ratelimit() has the RATELIMIT_MSG_ON_RELEASE flag exactly
for this purpose, so we set the flag.
Fixes: 4e00b339e264 ("random: rate limit unseeded randomness warnings")
Cc: stable@xxxxxxxxxxxxxxx
Reported-by: Jon Hunter <jonathanh@xxxxxxxxxx>
Reported-by: Ron Economos <re@xxxxxxxx>
Tested-by: Ron Economos <re@xxxxxxxx>
Signed-off-by: Jason A. Donenfeld <Jason@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/char/random.c | 2 +-
include/linux/ratelimit.h | 12 ++++++++----
2 files changed, 9 insertions(+), 5 deletions(-)
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -88,7 +88,7 @@ static RAW_NOTIFIER_HEAD(random_ready_ch
/* Control how we warn userspace. */
static struct ratelimit_state urandom_warning =
- RATELIMIT_STATE_INIT("warn_urandom_randomness", HZ, 3);
+ RATELIMIT_STATE_INIT_FLAGS("urandom_warning", HZ, 3, RATELIMIT_MSG_ON_RELEASE);
static int ratelimit_disable __read_mostly =
IS_ENABLED(CONFIG_WARN_ALL_UNSEEDED_RANDOM);
module_param_named(ratelimit_disable, ratelimit_disable, int, 0644);
--- a/include/linux/ratelimit.h
+++ b/include/linux/ratelimit.h
@@ -23,12 +23,16 @@ struct ratelimit_state {
unsigned long flags;
};
-#define RATELIMIT_STATE_INIT(name, interval_init, burst_init) { \
- .lock = __RAW_SPIN_LOCK_UNLOCKED(name.lock), \
- .interval = interval_init, \
- .burst = burst_init, \
+#define RATELIMIT_STATE_INIT_FLAGS(name, interval_init, burst_init, flags_init) { \
+ .lock = __RAW_SPIN_LOCK_UNLOCKED(name.lock), \
+ .interval = interval_init, \
+ .burst = burst_init, \
+ .flags = flags_init, \
}
+#define RATELIMIT_STATE_INIT(name, interval_init, burst_init) \
+ RATELIMIT_STATE_INIT_FLAGS(name, interval_init, burst_init, 0)
+
#define RATELIMIT_STATE_INIT_DISABLED \
RATELIMIT_STATE_INIT(ratelimit_state, 0, DEFAULT_RATELIMIT_BURST)
Patches currently in stable-queue which might be from Jason@xxxxxxxxx are
queue-5.4/random-schedule-mix_interrupt_randomness-less-often.patch
queue-5.4/random-quiet-urandom-warning-ratelimit-suppression-message.patch
