[syzbot] [kernel?] UBSAN: shift-out-of-bounds in pcl726_attach

[syzbot <syzbot+5cd373521edd68bebcb3@syzkaller.appspotmail.com>]

Hello,

syzbot found the following issue on:

HEAD commit:    c435a4f487e8 Merge tag 'riscv-for-linus-6.16-rc5' of git:/..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=14ea4f70580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=5ba6cef8f153bfeb
dashboard link: https://syzkaller.appspot.com/bug?extid=5cd373521edd68bebcb3
compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1116c582580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=12ea4f70580000

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-c435a4f4.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/691cd7284e87/vmlinux-c435a4f4.xz
kernel image: https://storage.googleapis.com/syzbot-assets/e61b1a511aab/bzImage-c435a4f4.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5cd373521edd68bebcb3@syzkaller.appspotmail.com

------------[ cut here ]------------
UBSAN: shift-out-of-bounds in drivers/comedi/drivers/pcl726.c:331:46
shift exponent -2147450880 is negative
CPU: 2 UID: 0 PID: 6107 Comm: syz.0.16 Not tainted 6.16.0-rc4-syzkaller-00286-gc435a4f487e8 #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 lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x16c/0x1f0 lib/dump_stack.c:120
 ubsan_epilogue lib/ubsan.c:233 [inline]
 __ubsan_handle_shift_out_of_bounds+0x27f/0x420 lib/ubsan.c:494
 pcl726_attach.cold+0x19/0x1e drivers/comedi/drivers/pcl726.c:331
 comedi_device_attach+0x3b0/0x900 drivers/comedi/drivers.c:996
 do_devconfig_ioctl+0x1a7/0x580 drivers/comedi/comedi_fops.c:855
 comedi_unlocked_ioctl+0x15bb/0x2e90 drivers/comedi/comedi_fops.c:2136
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:907 [inline]
 __se_sys_ioctl fs/ioctl.c:893 [inline]
 __x64_sys_ioctl+0x18b/0x210 fs/ioctl.c:893
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcefa58e929
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:00007ffd9f2c5a28 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fcefa7b5fa0 RCX: 00007fcefa58e929
RDX: 0000200000002b40 RSI: 0000000040946400 RDI: 0000000000000003
RBP: 00007fcefa610b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fcefa7b5fa0 R14: 00007fcefa7b5fa0 R15: 0000000000000003
 </TASK>
---[ end trace ]---


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