Kernel panic in gsch_scan_exclusion_write() of third party kernel module gsch

Issue

• System crashed with following messages in the kernel ring buffer:

[  584.324996] gsch: loading vfs-filter 9.5.3.7814: OK
[  584.333644] gsch_dev_open() doing
[  584.333647] gsch_dev_open() done: pid:1874(ds_am)
[  584.333695] BUG: unable to handle kernel paging request at 00007f78e059c0bc
[  584.333729] IP: [<ffffffffc0943a47>] gsch_scan_exclusion_write+0xa7/0x430 [gsch]
[  584.333758] PGD 202e605067 PUD 2033b49067 PMD 2036f63067 PTE 10348fa025
[  584.333786] Oops: 0001 [#1] SMP 
[  584.333801] Modules linked in: gsch(OE) redirfs(OE) sctp_diag sctp tcp_diag udp_diag dccp_diag dccp inet_diag unix_diag af_packet_diag netlink_diag xt_CHECKSUM iptable_mangle
[  584.334275] CPU: 13 PID: 1902 Comm: ds_am Tainted: G           OE  ------------   3.10.0-693.el7.x86_64 #1
[  584.334303] Hardware name: FUJITSU PRIMERGY CX2570 M4/D3854-A1, BIOS V1.0.0.0 R1.29.0 for D3854-A1x            03/29/2018
[  584.334335] task: ffff881027aedee0 ti: ffff88101b64c000 task.ti: ffff88101b64c000
[  584.334358] RIP: 0010:[<ffffffffc0943a47>]  [<ffffffffc0943a47>] gsch_scan_exclusion_write+0xa7/0x430 [gsch]
[  584.334623] Stack:
[  584.334632]  0000000000000001 0000000000000001 ffff88101b64ff48 ffffffff81203c58
[  584.334660]  ffff88203ad2ba10 00000000d75caeda ffff881f613006c0 00007f78e059c0bc
[  584.334687]  ffff88101b64ff48 0000000000000001 0000000000000000 ffff88101b64fef0
[  584.334715] Call Trace:
[  584.334731]  [<ffffffff81203c58>] ? __sb_start_write+0x58/0x110
[  584.334753]  [<ffffffff8127018d>] proc_reg_write+0x3d/0x80
[  584.334771]  [<ffffffff81200d2d>] vfs_write+0xbd/0x1e0
[  584.334789]  [<ffffffff81211c3d>] ? putname+0x3d/0x60
[  584.334806]  [<ffffffff81201b3f>] SyS_write+0x7f/0xe0
[  584.334826]  [<ffffffff816b4fc9>] system_call_fastpath+0x16/0x1b
[  584.334844] Code: c4 30 5b 41 5c 41 5d 41 5e 41 5f 5d c3 0f 1f 80 00 00 00 00 48 63 db 4c 8d 24 db 49 c1 e4 03 4c 89 e3 48 81 c3 00 c5 94 c0 74 b9 <41> 0f b6 07 3c 0a 74 08 84 c0 0f 85 99 00 00 00 4c 8d 73 18 4c 
[  584.334988] RIP  [<ffffffffc0943a47>] gsch_scan_exclusion_write+0xa7/0x430 [gsch]
[  584.335016]  RSP <ffff88101b64fe78>
[  584.335906] CR2: 00007f78e059c0bc