From: Theodore Ts'o tytso@mit.edu
commit 58be0106c5306b939b07b4b8bf00669a20593f4b upstream.
Fixes: eb9d1bf079bb: "random: only read from /dev/random after its pool has received 128 bits" Reported-by: kernel test robot lkp@intel.com Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Jason A. Donenfeld Jason@zx2c4.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/char/random.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-)
--- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -774,8 +774,11 @@ retry: if (cmpxchg(&r->entropy_count, orig, entropy_count) != orig) goto retry;
- if (has_initialized) + if (has_initialized) { r->initialized = 1; + wake_up_interruptible(&random_read_wait); + kill_fasync(&fasync, SIGIO, POLL_IN); + }
trace_credit_entropy_bits(r->name, nbits, entropy_count >> ENTROPY_SHIFT, _RET_IP_); @@ -791,6 +794,13 @@ retry: entropy_bits = r->entropy_count >> ENTROPY_SHIFT; }
+ /* initialize the blocking pool if necessary */ + if (entropy_bits >= random_read_wakeup_bits && + !other->initialized) { + schedule_work(&other->push_work); + return; + } + /* should we wake readers? */ if (entropy_bits >= random_read_wakeup_bits && wq_has_sleeper(&random_read_wait)) { @@ -1992,8 +2002,8 @@ _random_read(int nonblock, char __user * return -EAGAIN;
wait_event_interruptible(random_read_wait, - ENTROPY_BITS(&input_pool) >= - random_read_wakeup_bits); + blocking_pool.initialized && + (ENTROPY_BITS(&input_pool) >= random_read_wakeup_bits)); if (signal_pending(current)) return -ERESTARTSYS; }