syzbot


divide error in comedi_inc_scan_progress

Status: upstream: reported on 2025/07/08 17:52
Subsystems: comedi
[Documentation on labels]
Reported-by: syzbot+af53dea94b16396bc646@syzkaller.appspotmail.com
First crash: 53d, last: 25d
Discussions (2)
Title Replies (including bot) Last reply
[syzbot] Monthly comedi report (Jul 2025) 0 (1) 2025/07/24 09:32
[syzbot] [kernel?] divide error in comedi_inc_scan_progress 0 (1) 2025/07/08 17:52
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.6 divide error in comedi_inc_scan_progress 2 2 36d 39d 0/2 upstream: reported on 2025/07/22 05:26

Sample crash report:
Oops: divide error: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 15590 Comm: syz.0.2645 Not tainted 6.16.0-syzkaller-04405-g4b290aae788e #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:comedi_inc_scan_progress+0x1a4/0x430 drivers/comedi/drivers.c:563
Code: b6 0c 19 84 c9 0f 85 bd 01 00 00 03 45 2c 4c 8d a5 80 00 00 00 4c 89 e1 48 c1 e9 03 0f b6 0c 19 84 c9 0f 85 cc 01 00 00 31 d2 <41> f7 34 24 41 89 17 45 89 ec eb 0f e8 6b 84 dd f8 48 bb 00 00 00
RSP: 0018:ffffc90000007c80 EFLAGS: 00010046
RAX: 0000000000000001 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff888030da3800 R08: dffffc0000000000 R09: 1ffff11005e97c00
R10: dffffc0000000000 R11: ffffed1005e97c01 R12: ffff888030da3880
R13: 0000000000000002 R14: 0000000000000000 R15: ffff888030da382c
FS:  00007fb06a4a16c0(0000) GS:ffff888125c86000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c3965a8 CR3: 000000007e3bf000 CR4: 0000000000350ef0
Call Trace:
 <IRQ>
 comedi_buf_write_samples+0x373/0x5a0 drivers/comedi/comedi_buf.c:603
 parport_interrupt+0xf3/0x150 drivers/comedi/drivers/comedi_parport.c:218
 __handle_irq_event_percpu+0x28c/0x980 kernel/irq/handle.c:158
 handle_irq_event_percpu kernel/irq/handle.c:193 [inline]
 handle_irq_event+0x8b/0x1e0 kernel/irq/handle.c:210
 handle_edge_irq+0x23b/0x9f0 kernel/irq/chip.c:849
 generic_handle_irq_desc include/linux/irqdesc.h:173 [inline]
 handle_irq arch/x86/kernel/irq.c:254 [inline]
 call_irq_handler arch/x86/kernel/irq.c:266 [inline]
 __common_interrupt+0x143/0x250 arch/x86/kernel/irq.c:292
 common_interrupt+0xb6/0xe0 arch/x86/kernel/irq.c:285
 </IRQ>
 <TASK>
 asm_common_interrupt+0x26/0x40 arch/x86/include/asm/idtentry.h:693
RIP: 0010:__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:152 [inline]
RIP: 0010:_raw_spin_unlock_irqrestore+0xa8/0x110 kernel/locking/spinlock.c:194
Code: 74 05 e8 9b 68 55 f6 48 c7 44 24 20 00 00 00 00 9c 8f 44 24 20 f6 44 24 21 02 75 4f f7 c3 00 02 00 00 74 01 fb bf 01 00 00 00 <e8> 43 41 1e f6 65 8b 05 0c c0 27 07 85 c0 74 40 48 c7 04 24 0e 36
RSP: 0018:ffffc9000ebdf9a0 EFLAGS: 00000206
RAX: c7bf3a6ff8f27200 RBX: 0000000000000212 RCX: c7bf3a6ff8f27200
RDX: 0000000000000006 RSI: ffffffff8d972dc6 RDI: 0000000000000001
RBP: ffffc9000ebdfa30 R08: ffffffff8fa050f7 R09: 1ffffffff1f40a1e
R10: dffffc0000000000 R11: fffffbfff1f40a1f R12: dffffc0000000000
R13: dffffc0000000000 R14: ffffffff99d93f20 R15: 1ffff92001d7bf34
 spin_unlock_irqrestore include/linux/spinlock.h:406 [inline]
 uart_port_unlock_irqrestore include/linux/serial_core.h:788 [inline]
 autoconfig drivers/tty/serial/8250/8250_port.c:1198 [inline]
 serial8250_config_port+0x1451/0x5370 drivers/tty/serial/8250/8250_port.c:3137
 univ8250_config_port+0x3d7/0x9a0 drivers/tty/serial/8250/8250_rsa.c:70
 uart_do_autoconfig drivers/tty/serial/serial_core.c:1183 [inline]
 uart_ioctl+0x14d1/0x19c0 drivers/tty/serial/serial_core.c:1588
 tty_ioctl+0x929/0xde0 drivers/tty/tty_io.c:2792
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:598 [inline]
 __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:584
 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: 0033:0x7fb06958e9a9
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:00007fb06a4a1038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fb0697b6160 RCX: 00007fb06958e9a9
RDX: 0000000000000000 RSI: 0000000000005453 RDI: 000000000000000a
RBP: 00007fb069610d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fb0697b6160 R15: 00007ffcc15fb738
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:comedi_inc_scan_progress+0x1a4/0x430 drivers/comedi/drivers.c:563
Code: b6 0c 19 84 c9 0f 85 bd 01 00 00 03 45 2c 4c 8d a5 80 00 00 00 4c 89 e1 48 c1 e9 03 0f b6 0c 19 84 c9 0f 85 cc 01 00 00 31 d2 <41> f7 34 24 41 89 17 45 89 ec eb 0f e8 6b 84 dd f8 48 bb 00 00 00
RSP: 0018:ffffc90000007c80 EFLAGS: 00010046
RAX: 0000000000000001 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff888030da3800 R08: dffffc0000000000 R09: 1ffff11005e97c00
R10: dffffc0000000000 R11: ffffed1005e97c01 R12: ffff888030da3880
R13: 0000000000000002 R14: 0000000000000000 R15: ffff888030da382c
FS:  00007fb06a4a16c0(0000) GS:ffff888125c86000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c3965a8 CR3: 000000007e3bf000 CR4: 0000000000350ef0
----------------
Code disassembly (best guess):
   0:	b6 0c                	mov    $0xc,%dh
   2:	19 84 c9 0f 85 bd 01 	sbb    %eax,0x1bd850f(%rcx,%rcx,8)
   9:	00 00                	add    %al,(%rax)
   b:	03 45 2c             	add    0x2c(%rbp),%eax
   e:	4c 8d a5 80 00 00 00 	lea    0x80(%rbp),%r12
  15:	4c 89 e1             	mov    %r12,%rcx
  18:	48 c1 e9 03          	shr    $0x3,%rcx
  1c:	0f b6 0c 19          	movzbl (%rcx,%rbx,1),%ecx
  20:	84 c9                	test   %cl,%cl
  22:	0f 85 cc 01 00 00    	jne    0x1f4
  28:	31 d2                	xor    %edx,%edx
* 2a:	41 f7 34 24          	divl   (%r12) <-- trapping instruction
  2e:	41 89 17             	mov    %edx,(%r15)
  31:	45 89 ec             	mov    %r13d,%r12d
  34:	eb 0f                	jmp    0x45
  36:	e8 6b 84 dd f8       	call   0xf8dd84a6
  3b:	48                   	rex.W
  3c:	bb                   	.byte 0xbb
  3d:	00 00                	add    %al,(%rax)

Crashes (27):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/30 14:59 upstream 4b290aae788e f8f2b4da .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root divide error in comedi_inc_scan_progress
2025/07/30 06:21 upstream 86aa72182095 f8f2b4da .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root divide error in comedi_inc_scan_progress
2025/07/30 06:21 upstream 86aa72182095 f8f2b4da .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root divide error in comedi_inc_scan_progress
2025/07/24 07:08 upstream 01a412d06bc5 0c1d6ded .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root divide error in comedi_inc_scan_progress
2025/07/23 16:03 upstream 89be9a83ccf1 e1dd4f22 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root divide error in comedi_inc_scan_progress
2025/07/23 13:01 upstream 89be9a83ccf1 e1dd4f22 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root divide error in comedi_inc_scan_progress
2025/07/22 16:47 upstream 89be9a83ccf1 85deaf45 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root divide error in comedi_inc_scan_progress
2025/07/22 06:39 upstream 89be9a83ccf1 1555463b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root divide error in comedi_inc_scan_progress
2025/07/21 15:39 upstream 89be9a83ccf1 0b3788a0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root divide error in comedi_inc_scan_progress
2025/07/21 12:58 upstream 89be9a83ccf1 0b3788a0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root divide error in comedi_inc_scan_progress
2025/07/09 03:38 upstream d006330be3f7 abade794 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root divide error in comedi_inc_scan_progress
2025/07/08 03:22 upstream d7b8f8e20813 4f67c4ae .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root divide error in comedi_inc_scan_progress
2025/07/08 00:11 upstream d7b8f8e20813 4f67c4ae .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root divide error in comedi_inc_scan_progress
2025/08/05 02:45 linux-next 5c5a10f0be96 abdcb213 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce divide error in comedi_inc_scan_progress
2025/08/04 15:46 linux-next 5c5a10f0be96 7368264b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce divide error in comedi_inc_scan_progress
2025/07/31 01:56 linux-next d086c886ceb9 f8f2b4da .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce divide error in comedi_inc_scan_progress
2025/07/30 07:57 linux-next d086c886ceb9 f8f2b4da .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce divide error in comedi_inc_scan_progress
2025/07/29 04:41 linux-next d086c886ceb9 c4a95487 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce divide error in comedi_inc_scan_progress
2025/07/27 00:47 linux-next d086c886ceb9 fb8f743d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce divide error in comedi_inc_scan_progress
2025/07/24 15:51 linux-next d086c886ceb9 fb8f743d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce divide error in comedi_inc_scan_progress
2025/07/24 15:50 linux-next d086c886ceb9 fb8f743d .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce divide error in comedi_inc_scan_progress
2025/07/24 11:15 linux-next d086c886ceb9 0c1d6ded .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce divide error in comedi_inc_scan_progress
2025/07/24 06:12 linux-next d086c886ceb9 0c1d6ded .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce divide error in comedi_inc_scan_progress
2025/07/22 09:29 linux-next d086c886ceb9 1555463b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce divide error in comedi_inc_scan_progress
2025/07/22 06:07 linux-next d086c886ceb9 1555463b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce divide error in comedi_inc_scan_progress
2025/07/22 03:45 linux-next d086c886ceb9 0b3788a0 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root divide error in comedi_inc_scan_progress
2025/07/20 09:40 linux-next d086c886ceb9 7117feec .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root divide error in comedi_inc_scan_progress
* Struck through repros no longer work on HEAD.