[syzbot] [kernel?] UBSAN: shift-out-of-bounds in pcl812_attach

[syzbot <syzbot+32de323b0addb9e114ff@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    4c06e63b9203 Merge tag 'for-6.16-rc4-tag' of git://git.ker..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=104a8f70580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=b29b1a0d7330d4a8
dashboard link: https://syzkaller.appspot.com/bug?extid=32de323b0addb9e114ff
compiler:       Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=16b17ebc580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=144a8f70580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-4c06e63b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ff61efc838cb/vmlinux-4c06e63b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/dea44d0d14bb/bzImage-4c06e63b.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+32de323b0addb9e114ff@syzkaller.appspotmail.com

------------[ cut here ]------------
UBSAN: shift-out-of-bounds in drivers/comedi/drivers/pcl812.c:1152:10
shift exponent 8550 is too large for 32-bit type 'int'
CPU: 0 UID: 0 PID: 5465 Comm: syz.0.16 Not tainted 6.16.0-rc4-syzkaller-00123-g4c06e63b9203 #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
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 ubsan_epilogue+0xa/0x40 lib/ubsan.c:233
 __ubsan_handle_shift_out_of_bounds+0x386/0x410 lib/ubsan.c:494
 pcl812_attach+0x1b9e/0x2300 drivers/comedi/drivers/pcl812.c:1152
 comedi_device_attach+0x51d/0x670 drivers/comedi/drivers.c:996
 do_devconfig_ioctl drivers/comedi/comedi_fops.c:855 [inline]
 comedi_unlocked_ioctl+0x686/0xf40 drivers/comedi/comedi_fops.c:2136
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl+0xf9/0x170 fs/ioctl.c:893
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fed6198e929
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:00007ffd34893f98 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fed61bb5fa0 RCX: 00007fed6198e929
RDX: 0000200000000140 RSI: 0000000040946400 RDI: 0000000000000003
RBP: 00007fed61a10b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fed61bb5fa0 R14: 00007fed61bb5fa0 R15: 0000000000000003
 </TASK>
---[ end trace ]---


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