Kernel panic at ptyx_master_chars_in_buffer.

Issue

• Kernel panic:

Perle TruePort Driver v6.6.0 unloading                                      <<<<================
Perle TruePort Driver v6.6.0, Initializing 256 ports                        <<<<================
Perle TruePort Driver v6.6.0 unloading                                      <<<<================
Perle TruePort Driver v6.6.0, Initializing 256 ports                        <<<<================
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<ffffffffa005128a>] ptyx_master_chars_in_buffer+0x4a/0x70 [ptyx]
PGD 220396067 PUD 212d28067 PMD 0 
Oops: 0000 [#1] SMP 
last sysfs file: /sys/module/ptyx/initstate
.........
Code: 9c 24 e8 00 00 00 48 89 df e8 23 ec 4b e1 4d 8b a4 24 b8 00 00 00 48 89 c6 48 89 df e8 80 ed 4b e1 4d 85 e4 74 1d 49 8b 44 24 40 <48> 8b 00 48 8b 40 30 48 85 c0 74 0c 4c 89 e7 ff d0 3d ff 07 00 
RIP  [<ffffffffa005128a>] ptyx_master_chars_in_buffer+0x4a/0x70 [ptyx]
 RSP <ffff88010e8a3938>
CR2: 0000000000000000