lkml.org 
[lkml]   [2022]   [Jun]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 4.19 072/234] random: continually use hwgenerator randomness
    Date
    From: Dominik Brodowski <linux@dominikbrodowski.net>

    commit c321e907aa4803d562d6e70ebed9444ad082f953 upstream.

    The rngd kernel thread may sleep indefinitely if the entropy count is
    kept above random_write_wakeup_bits by other entropy sources. To make
    best use of multiple sources of randomness, mix entropy from hardware
    RNGs into the pool at least once within CRNG_RESEED_INTERVAL.

    Cc: Herbert Xu <herbert@gondor.apana.org.au>
    Cc: Jason A. Donenfeld <Jason@zx2c4.com>
    Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
    Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
    Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
    ---
    drivers/char/random.c | 10 ++++++----
    1 file changed, 6 insertions(+), 4 deletions(-)

    --- a/drivers/char/random.c
    +++ b/drivers/char/random.c
    @@ -2193,13 +2193,15 @@ void add_hwgenerator_randomness(const ch
    return;
    }

    - /* Suspend writing if we're above the trickle threshold.
    + /* Throttle writing if we're above the trickle threshold.
    * We'll be woken up again once below random_write_wakeup_thresh,
    - * or when the calling thread is about to terminate.
    + * when the calling thread is about to terminate, or once
    + * CRNG_RESEED_INTERVAL has lapsed.
    */
    - wait_event_interruptible(random_write_wait,
    + wait_event_interruptible_timeout(random_write_wait,
    !system_wq || kthread_should_stop() ||
    - POOL_ENTROPY_BITS() <= random_write_wakeup_bits);
    + POOL_ENTROPY_BITS() <= random_write_wakeup_bits,
    + CRNG_RESEED_INTERVAL);
    mix_pool_bytes(buffer, count);
    credit_entropy_bits(entropy);
    }

    \
     
     \ /
      Last update: 2022-06-23 20:01    [W:4.776 / U:0.060 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site