Re: eb9d1bf079 [ 88.881528] EIP: _random_read

[Theodore Ts'o]

Can you check and see if this addresses the issue?  I'm not able to
easily repro the softlockup.

Thanks!

                                                - Ted

commit f93d3e94983bf8b4697ceb121c79afd941862860
Author: Theodore Ts'o <ty...@mit.edu>
Date:   Wed May 22 12:02:16 2019 -0400

    random: fix soft lockup when trying to read from an uninitialized blocking 
pool
    
    Fixes: eb9d1bf079bb: "random: only read from /dev/random after its pool has 
received 128 bits"
    Reported-by: kernel test robot <l...@intel.com>
    Signed-off-by: Theodore Ts'o <ty...@mit.edu>

diff --git a/drivers/char/random.c b/drivers/char/random.c
index a42b3d764da8..9cea93d0bfb3 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -1936,8 +1936,8 @@ _random_read(int nonblock, char __user *buf, size_t 
nbytes)
                        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;
        }