------------[ cut here ]------------
UBSAN: shift-out-of-bounds in drivers/comedi/drivers/pcl726.c:331:46
shift exponent -4 is negative
CPU: 1 UID: 0 PID: 16732 Comm: syz.0.3529 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250
 ubsan_epilogue+0xa/0x40
 __ubsan_handle_shift_out_of_bounds+0x386/0x410
 pcl726_attach+0xac4/0xd50
 comedi_device_attach+0x51f/0x720
 comedi_unlocked_ioctl+0x5ff/0x1020
 __se_sys_ioctl+0xfc/0x170
 do_syscall_64+0xfa/0x3b0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fef3398ebe9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fef3480a038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fef33bb5fa0 RCX: 00007fef3398ebe9
RDX: 00002000000005c0 RSI: 0000000040946400 RDI: 0000000000000003
RBP: 00007fef33a11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fef33bb6038 R14: 00007fef33bb5fa0 R15: 00007ffeba16ac58
 </TASK>
---[ end trace ]---
