Kernel panic in custom_file_release function due to third party kernel module fileaccess_mod

Issue

• The server crashed with error "BUG: unable to handle kernel NULL pointer dereference at 0000000000000090" in the function custom_file_release+0xcb/0x150 [fileaccess_mod].

<1>BUG: unable to handle kernel NULL pointer dereference at 0000000000000090
<1>IP: [<ffffffffa0690f2b>] custom_file_release+0xcb/0x150 [fileaccess_mod]
[...]
<4>Stack:
<4> 0000000000000000 0000000000000000 0000000000000000 0000000000000000
<4><d> 0000000000000000 ffffffff8155e351 000000000323ee60 00000000037fa880
<4><d> 000000000323ee30 00007fd9740030d0 00007fd98d8bdee0 00000000035da300
<4>Call Trace:
<4> [<ffffffff8155e351>] system_call_fastpath+0x2f/0x34
<4>Code: 83 78 38 00 74 ca 41 f6 44 24 3c 02 74 c2 65 48 8b 04 25 00 fc 00 00 8b b8 a8 04 00 00 e8 4e 50 00 00 84 c0 75 aa 49 8b 44 24 18 <48> 8b 80 90 00 00 00 48 8b 40 30 48 8b 38 e8 32 fe ff ff 84 c0 
<1>RIP  [<ffffffffa0690f2b>] custom_file_release+0xcb/0x150 [fileaccess_mod]
<4> RSP <ffff881d67363f28>
<4>CR2: 0000000000000090