BUG: kernel NULL pointer dereference, address: 0000000000000000
#PF: supervisor instruction fetch in kernel mode
#PF: error_code(0x0010) - not-present page
PGD 6aca7067 P4D 6aca7067 PUD 70cef067 PMD 0 
Oops: Oops: 0010 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 7299 Comm: syz.2.380 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffc9000f61fba0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 000000000000484c RCX: ffffc9000c4d2000
RDX: ffff88806fbc0008 RSI: 000000000000484c RDI: ffff888049ff1800
RBP: ffff88806fbc0004 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff888049ff1800
R13: ffff88806fbc0000 R14: 0000000000000001 R15: 0000000000000003
FS:  0000000000000000(0000) GS:ffff8880974c3000(0063) knlGS:00000000f54e6b40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000000777b5000 CR4: 0000000000352ef0
Call Trace:
 <TASK>
 get_valid_routes drivers/comedi/comedi_fops.c:1322 [inline]
 parse_insn+0x78c/0x1970 drivers/comedi/comedi_fops.c:1401
 do_insn_ioctl+0x152/0x4e0 drivers/comedi/comedi_fops.c:1679
 compat_insn drivers/comedi/comedi_fops.c:3227 [inline]
 comedi_compat_ioctl+0x327/0x990 drivers/comedi/comedi_fops.c:3276
 __do_compat_sys_ioctl fs/ioctl.c:696 [inline]
 __se_compat_sys_ioctl fs/ioctl.c:639 [inline]
 __ia32_compat_sys_ioctl+0x242/0x370 fs/ioctl.c:639
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
 __do_fast_syscall_32+0x7c/0x3a0 arch/x86/entry/syscall_32.c:306
 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:331
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf7fc2579
Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00
RSP: 002b:00000000f54e655c EFLAGS: 00000296 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000005 RCX: 000000008020640c
RDX: 0000000080024600 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
Modules linked in:
CR2: 0000000000000000
---[ end trace 0000000000000000 ]---
RIP: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffc9000f61fba0 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 000000000000484c RCX: ffffc9000c4d2000
RDX: ffff88806fbc0008 RSI: 000000000000484c RDI: ffff888049ff1800
RBP: ffff88806fbc0004 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000000 R12: ffff888049ff1800
R13: ffff88806fbc0000 R14: 0000000000000001 R15: 0000000000000003
FS:  0000000000000000(0000) GS:ffff8880974c3000(0063) knlGS:00000000f54e6b40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 00000000777b5000 CR4: 0000000000352ef0
----------------
Code disassembly (best guess), 2 bytes skipped:
   0:	10 06                	adc    %al,(%rsi)
   2:	03 74 b4 01          	add    0x1(%rsp,%rsi,4),%esi
   6:	10 07                	adc    %al,(%rdi)
   8:	03 74 b0 01          	add    0x1(%rax,%rsi,4),%esi
   c:	10 08                	adc    %cl,(%rax)
   e:	03 74 d8 01          	add    0x1(%rax,%rbx,8),%esi
  1e:	00 51 52             	add    %dl,0x52(%rcx)
  21:	55                   	push   %rbp
  22:	89 e5                	mov    %esp,%ebp
  24:	0f 34                	sysenter
  26:	cd 80                	int    $0x80
* 28:	5d                   	pop    %rbp <-- trapping instruction
  29:	5a                   	pop    %rdx
  2a:	59                   	pop    %rcx
  2b:	c3                   	ret
  2c:	90                   	nop
  2d:	90                   	nop
  2e:	90                   	nop
  2f:	90                   	nop
  30:	8d b4 26 00 00 00 00 	lea    0x0(%rsi,%riz,1),%esi
  37:	8d b4 26 00 00 00 00 	lea    0x0(%rsi,%riz,1),%esi