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AKwUvBzWCnjfedU6huSQ8zyaxETzzeEr9pNZXVWM9yyg0+rekfr7PvRslSAc4TmFmVC5mNJcmcfuM8PtERfxLak=@vger.kernel.org X-Gm-Message-State: AFuF++mUz8kx7wJGMDzlv45fezkOe/LcHsR/XxLu2n7OouBMMh6oJKE6 xnIR9uatCDw/bvJudCgSqvloEysSTDWP9umH2mibGDSRKFWubpWMiRrOw8nRXlHnfAodLiJyJSB cEf2e/Zo8v3xbHj19ls0mzjubcJgM+RB+bxeIslTY3Q+G7qkO0sCqasFwjC4= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:a0b:b0:6c9:8460:c85d with SMTP id 006d021491bc7-6ca9d44ebd6mr10566817eaf.69.1790054976499; Mon, 21 Sep 2026 22:29:36 -0700 (PDT) Date: Mon, 21 Sep 2026 22:29:36 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6ab21240.e548f532.1ca396.0018.GAE@google.com> Subject: [syzbot] [comedi?] UBSAN: shift-out-of-bounds in dt2811_attach From: syzbot To: abbotti@mev.co.uk, hsweeten@visionengravers.com, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 93f51579e7df Linux 7.3-rc4 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=17b45005580000 kernel config: https://syzkaller.appspot.com/x/.config?x=7d012d9c67977ee4 dashboard link: https://syzkaller.appspot.com/bug?extid=a4cedab706d0a8a3f988 compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=106ff005580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10d054c9580000 Downloadable assets: disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-93f51579.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/00f02ade84ed/vmlinux-93f51579.xz kernel image: https://storage.googleapis.com/syzbot-assets/93be890b3b79/bzImage-93f51579.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+a4cedab706d0a8a3f988@syzkaller.appspotmail.com ------------[ cut here ]------------ UBSAN: shift-out-of-bounds in drivers/comedi/drivers/dt2811.c:570:31 shift exponent -251 is negative CPU: 0 UID: 0 PID: 5925 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 ubsan_epilogue+0xa/0x30 lib/ubsan.c:233 __ubsan_handle_shift_out_of_bounds+0x279/0x2a0 lib/ubsan.c:494 dt2811_attach.cold+0x19/0x1e drivers/comedi/drivers/dt2811.c:570 comedi_device_attach+0x40e/0x6b0 drivers/comedi/drivers.c:1101 do_devconfig_ioctl+0x1b3/0x6d0 drivers/comedi/comedi_fops.c:930 comedi_unlocked_ioctl+0x860/0x3310 drivers/comedi/comedi_fops.c:2302 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline] do_syscall_64+0x123/0x790 arch/x86/entry/syscall_64.c:84 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe50959e159 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffcc3e899c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007fe509825fa0 RCX: 00007fe50959e159 RDX: 0000200000000100 RSI: 0000000040946400 RDI: 0000000000000003 RBP: 00007fe50963506b R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe509825fac R14: 00007fe509825fa0 R15: 00007fe509825fa0 ---[ end trace ]--- --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing. If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup