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: 104d, last: 26d
Discussions (3)
Title Replies (including bot) Last reply
[syzbot] [kernel?] divide error in comedi_inc_scan_progress 1 (2) 2025/10/16 11:05
[syzbot] Monthly comedi report (Sep 2025) 0 (1) 2025/09/24 12:39
[syzbot] Monthly comedi report (Jul 2025) 0 (1) 2025/07/24 09:32
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 87d 90d 0/2 upstream: reported on 2025/07/22 05:26

Sample crash report:
Oops: divide error: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 11660 Comm: irq/7-comedi_pa Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
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 3b e1 55 f9 48 bb 00 00 00
RSP: 0018:ffffc9000512fac0 EFLAGS: 00010246
RAX: 0000000000000001 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff88804a72b400 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed10089f8001 R12: ffff88804a72b480
R13: 0000000000000002 R14: 0000000000000000 R15: ffff88804a72b42c
FS:  0000000000000000(0000) GS:ffff8881268bc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f990ba056c0 CR3: 0000000028634000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
Call Trace:
 <TASK>
 comedi_buf_write_samples+0x373/0x5a0 drivers/comedi/comedi_buf.c:603
 parport_interrupt+0xf3/0x150 drivers/comedi/drivers/comedi_parport.c:218
 irq_thread_fn kernel/irq/manage.c:1131 [inline]
 irq_forced_thread_fn+0x98/0x120 kernel/irq/manage.c:1153
 irq_thread+0x427/0x690 kernel/irq/manage.c:1256
 kthread+0x70e/0x8a0 kernel/kthread.c:463
 ret_from_fork+0x436/0x7d0 arch/x86/kernel/process.c:148
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </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 3b e1 55 f9 48 bb 00 00 00
RSP: 0018:ffffc9000512fac0 EFLAGS: 00010246
RAX: 0000000000000001 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffff88804a72b400 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffed10089f8001 R12: ffff88804a72b480
R13: 0000000000000002 R14: 0000000000000000 R15: ffff88804a72b42c
FS:  0000000000000000(0000) GS:ffff8881268bc000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f990ba056c0 CR3: 0000000028634000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000600
----------------
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 3b e1 55 f9       	call   0xf955e176
  3b:	48                   	rex.W
  3c:	bb                   	.byte 0xbb
  3d:	00 00                	add    %al,(%rax)

Crashes (28):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/09/23 20:36 upstream cec1e6e5d1ab 0abd0691 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root divide error in comedi_inc_scan_progress
2025/07/30 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.