syzbot


UBSAN: shift-out-of-bounds in das16m1_attach

Status: upstream: reported C repro on 2025/07/04 16:20
Subsystems: kernel
[Documentation on labels]
Reported-by: syzbot+c52293513298e0fd9a94@syzkaller.appspotmail.com
First crash: 1d17h, last: 3h46m
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [kernel?] UBSAN: shift-out-of-bounds in das16m1_attach 1 (3) 2025/07/04 19:00
Last patch testing requests (1)
Created Duration User Patch Repo Result
2025/07/04 18:11 47m enjuk@amazon.com patch upstream OK log

Sample crash report:
UBSAN: shift-out-of-bounds in drivers/comedi/drivers/das16m1.c:525:9
shift exponent 67108867 is too large for 32-bit type 'int'
CPU: 0 UID: 0 PID: 6101 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 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
 das16m1_attach.cold+0x19/0x1e drivers/comedi/drivers/das16m1.c:525
 comedi_device_attach+0x3b3/0x900 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: 0033:0x7f1d8718e929
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:00007ffe20aa5098 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f1d873b5fa0 RCX: 00007f1d8718e929
RDX: 0000200000000080 RSI: 0000000040946400 RDI: 0000000000000003
RBP: 00007f1d87210b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1d873b5fa0 R14: 00007f1d873b5fa0 R15: 0000000000000003
 </TASK>
---[ end trace ]---

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/04 15:05 upstream 4c06e63b9203 d869b261 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream UBSAN: shift-out-of-bounds in das16m1_attach
2025/07/04 14:47 upstream 4c06e63b9203 d869b261 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream UBSAN: shift-out-of-bounds in das16m1_attach
2025/07/06 04:35 upstream 05df91921da6 4f67c4ae .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root UBSAN: shift-out-of-bounds in das16m1_attach
2025/07/05 06:31 upstream c435a4f487e8 4f67c4ae .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root UBSAN: shift-out-of-bounds in das16m1_attach
2025/07/04 14:30 upstream 4c06e63b9203 d869b261 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream UBSAN: shift-out-of-bounds in das16m1_attach
* Struck through repros no longer work on HEAD.