syzbot


UBSAN: shift-out-of-bounds in das16m1_attach

Status: upstream: reported on 2025/07/22 13:53
Reported-by: syzbot+a2c28845f45d1b1ebc79@syzkaller.appspotmail.com
First crash: 5d22h, last: 5d22h
Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 UBSAN: shift-out-of-bounds in das16m1_attach -1 6 5d22h 6d15h 0/3 upstream: reported on 2025/07/21 20:49
linux-5.15 UBSAN: shift-out-of-bounds in das16m1_attach origin:lts-only -1 C 5 10h35m 3d01h 0/3 upstream: reported C repro on 2025/07/25 10:13
upstream UBSAN: shift-out-of-bounds in das16m1_attach comedi -1 C 92 7d10h 23d 25/29 upstream: reported C repro on 2025/07/04 16:20

Sample crash report:
================================================================================
UBSAN: shift-out-of-bounds in drivers/comedi/drivers/das16m1.c:525:9
shift exponent 159 is too large for 32-bit type 'int'
CPU: 0 PID: 6759 Comm: syz.2.231 Not tainted 6.6.99-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
 ubsan_epilogue+0xa/0x30 lib/ubsan.c:217
 __ubsan_handle_shift_out_of_bounds+0x380/0x400 lib/ubsan.c:387
 das16m1_attach+0x8cd/0xb00 drivers/comedi/drivers/das16m1.c:525
 comedi_device_attach+0x519/0x660 drivers/comedi/drivers.c:995
 do_devconfig_ioctl drivers/comedi/comedi_fops.c:855 [inline]
 comedi_unlocked_ioctl+0x68d/0xf00 drivers/comedi/comedi_fops.c:2136
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:871 [inline]
 __se_sys_ioctl+0xfd/0x170 fs/ioctl.c:857
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f9efc98e9a9
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:00007f9efc7ff038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f9efcbb5fa0 RCX: 00007f9efc98e9a9
RDX: 0000200000000180 RSI: 0000000040946400 RDI: 0000000000000003
RBP: 00007f9efca10d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f9efcbb5fa0 R15: 00007fffbcd6d958
 </TASK>
================================================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/22 13:53 linux-6.6.y d96eb99e2f0e 1555463b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan UBSAN: shift-out-of-bounds in das16m1_attach
2025/07/22 13:52 linux-6.6.y d96eb99e2f0e 1555463b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan UBSAN: shift-out-of-bounds in das16m1_attach
* Struck through repros no longer work on HEAD.