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@vger.kernel.org Reported-by: Jon Hunter jonathanh@nvidia.com Reported-by: Ron Economos re@w6rz.net Tested-by: Ron Economos re@w6rz.net Signed-off-by: Jason A. Donenfeld Jason@zx2c4.com --- drivers/char/random.c | 2 +- include/linux/ratelimit.h | 12 ++++++++---- 2 files changed, 9 insertions(+), 5 deletions(-)
diff --git a/drivers/char/random.c b/drivers/char/random.c index 82f9ee440406..bb4793cf304e 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -88,7 +88,7 @@ static RAW_NOTIFIER_HEAD(random_ready_chain);
/* 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); diff --git a/include/linux/ratelimit.h b/include/linux/ratelimit.h index 8ddf79e9207a..1df12e8dde6f 100644 --- 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)