syzbot

Oops: divide error: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 3220 Comm: irq/7-das16m1 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:comedi_buf_munge drivers/comedi/comedi_buf.c:347 [inline]
RIP: 0010:comedi_buf_write_free+0x3c8/0x7e0 drivers/comedi/comedi_buf.c:391
Code: 41 03 45 00 48 8b 4c 24 78 42 0f b6 0c 21 84 c9 4c 8b bc 24 90 00 00 00 44 8b 74 24 54 0f 85 02 01 00 00 31 d2 48 8b 4c 24 30 <f7> 31 41 89 55 00 48 8b 44 24 70 42 0f b6 04 20 84 c0 0f 85 09 01
RSP: 0018:ffffc90004b87a18 EFLAGS: 00010246
RAX: 0000000000000001 RBX: dffffc0000000000 RCX: ffff8880650cd080
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff886ac6f0 R12: dffffc0000000000
R13: ffff8880650cd038 R14: 0000000000000000 R15: ffff8880650cd000
FS:  0000000000000000(0000) GS:ffff8881268c2000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff2e8d2b18 CR3: 000000002f5ea000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 comedi_buf_write_samples+0x369/0x5a0 drivers/comedi/comedi_buf.c:602
 das16m1_handler+0x213/0x4b0 drivers/comedi/drivers/das16m1.c:413
 das16m1_interrupt+0xaf/0x180 drivers/comedi/drivers/das16m1.c:470
 irq_thread_fn kernel/irq/manage.c:1131 [inline]
 irq_forced_thread_fn+0x98/0x120 kernel/irq/manage.c:1153
 irq_thread+0x427/0x690 kernel/irq/manage.c:1256
 kthread+0x711/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:comedi_buf_munge drivers/comedi/comedi_buf.c:347 [inline]
RIP: 0010:comedi_buf_write_free+0x3c8/0x7e0 drivers/comedi/comedi_buf.c:391
Code: 41 03 45 00 48 8b 4c 24 78 42 0f b6 0c 21 84 c9 4c 8b bc 24 90 00 00 00 44 8b 74 24 54 0f 85 02 01 00 00 31 d2 48 8b 4c 24 30 <f7> 31 41 89 55 00 48 8b 44 24 70 42 0f b6 04 20 84 c0 0f 85 09 01
RSP: 0018:ffffc90004b87a18 EFLAGS: 00010246
RAX: 0000000000000001 RBX: dffffc0000000000 RCX: ffff8880650cd080
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000002 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff886ac6f0 R12: dffffc0000000000
R13: ffff8880650cd038 R14: 0000000000000000 R15: ffff8880650cd000
FS:  0000000000000000(0000) GS:ffff8881268c2000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fff2e8d2b18 CR3: 000000002f5ea000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	41 03 45 00          	add    0x0(%r13),%eax
   4:	48 8b 4c 24 78       	mov    0x78(%rsp),%rcx
   9:	42 0f b6 0c 21       	movzbl (%rcx,%r12,1),%ecx
   e:	84 c9                	test   %cl,%cl
  10:	4c 8b bc 24 90 00 00 	mov    0x90(%rsp),%r15
  17:	00
  18:	44 8b 74 24 54       	mov    0x54(%rsp),%r14d
  1d:	0f 85 02 01 00 00    	jne    0x125
  23:	31 d2                	xor    %edx,%edx
  25:	48 8b 4c 24 30       	mov    0x30(%rsp),%rcx
* 2a:	f7 31                	divl   (%rcx) <-- trapping instruction
  2c:	41 89 55 00          	mov    %edx,0x0(%r13)
  30:	48 8b 44 24 70       	mov    0x70(%rsp),%rax
  35:	42 0f b6 04 20       	movzbl (%rax,%r12,1),%eax
  3a:	84 c0                	test   %al,%al
  3c:	0f                   	.byte 0xf
  3d:	85 09                	test   %ecx,(%rcx)
  3f:	01                   	.byte 0x1