syzbot


WARNING in comedi_unlocked_ioctl

Status: fixed on 2025/08/28 16:24
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+032ab98511c4a6864a8f@syzkaller.appspotmail.com
Fix commit: c9d3d9667443 comedi: Fail COMEDI_INSNLIST ioctl if n_insns is too large
First crash: 53d, last: 40d
Fix bisection: fixed by (bisect log) :
commit c9d3d9667443caafa804cd07940aeaef8e53aa90
Author: Ian Abbott <abbotti@mev.co.uk>
Date: Fri Jul 4 12:04:05 2025 +0000

  comedi: Fail COMEDI_INSNLIST ioctl if n_insns is too large

  
Bug presence (1)
Date Name Commit Repro Result
2025/07/12 upstream (ToT) 379f604cc3dc C [report] WARNING in comedi_unlocked_ioctl
Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING in comedi_unlocked_ioctl mm comedi -1 C 262 43d 60d 28/29 upstream: reported C repro on 2025/07/04 08:17
linux-5.15 WARNING in comedi_unlocked_ioctl origin:upstream -1 C 37 5d15h 54d 0/3 upstream: reported C repro on 2025/07/10 11:52
linux-6.1 WARNING in comedi_unlocked_ioctl origin:upstream -1 C done 13 42d 53d 3/3 fixed on 2025/08/26 15:31

Sample crash report:
------------[ cut here ]------------
WARNING: CPU: 1 PID: 6158 at mm/page_alloc.c:4433 __alloc_pages+0x2de/0x460 mm/page_alloc.c:4433
Modules linked in:
CPU: 1 PID: 6158 Comm: syz.2.63 Not tainted 6.6.99-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:__alloc_pages+0x2de/0x460 mm/page_alloc.c:4433
Code: 0c 25 28 00 00 00 48 3b 8c 24 a0 00 00 00 0f 85 a0 00 00 00 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 c6 05 43 1f 64 0c 01 <0f> 0b eb a5 a9 00 00 08 00 8b 74 24 0c 75 3e 44 89 f1 81 e1 7f ff
RSP: 0018:ffffc900032d79c0 EFLAGS: 00010246
RAX: ffffc900032d7a00 RBX: 1ffff9200065af3c RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffc900032d7a28
RBP: ffffc900032d7ac0 R08: ffffc900032d7a27 R09: 0000000000000000
R10: ffffc900032d7a00 R11: fffff5200065af45 R12: 000000000000001a
R13: 0000000000000000 R14: 0000000000040dc0 R15: dffffc0000000000
FS:  00007f04d63ad6c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2d61fffc CR3: 000000007681c000 CR4: 00000000003526e0
Call Trace:
 <TASK>
 __alloc_pages_node include/linux/gfp.h:237 [inline]
 alloc_pages_node include/linux/gfp.h:260 [inline]
 __kmalloc_large_node+0x8c/0x1e0 mm/slab_common.c:1148
 __do_kmalloc_node mm/slab_common.c:995 [inline]
 __kmalloc+0x111/0x240 mm/slab_common.c:1020
 kmalloc_array include/linux/slab.h:637 [inline]
 kcalloc include/linux/slab.h:668 [inline]
 comedi_unlocked_ioctl+0x9f0/0xf00 drivers/comedi/comedi_fops.c:2242
 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: 0033:0x7f04d558e9a9
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:00007f04d63ad038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f04d57b5fa0 RCX: 00007f04d558e9a9
RDX: 0000200000000000 RSI: 000000008010640b RDI: 0000000000000003
RBP: 00007f04d5610d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f04d57b5fa0 R15: 00007ffcdd829c38
 </TASK>

Crashes (9):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/24 05:16 linux-6.6.y d96eb99e2f0e 0c1d6ded .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in comedi_unlocked_ioctl
2025/07/24 05:16 linux-6.6.y d96eb99e2f0e 0c1d6ded .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in comedi_unlocked_ioctl
2025/07/23 17:45 linux-6.6.y d96eb99e2f0e e1dd4f22 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in comedi_unlocked_ioctl
2025/07/23 17:45 linux-6.6.y d96eb99e2f0e e1dd4f22 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in comedi_unlocked_ioctl
2025/07/21 05:14 linux-6.6.y d96eb99e2f0e 7117feec .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in comedi_unlocked_ioctl
2025/07/12 22:05 linux-6.6.y 59a2de10b81a 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in comedi_unlocked_ioctl
2025/07/12 22:05 linux-6.6.y 59a2de10b81a 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in comedi_unlocked_ioctl
2025/07/11 11:06 linux-6.6.y 59a2de10b81a 3cda49cf .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in comedi_unlocked_ioctl
2025/07/11 04:25 linux-6.6.y 59a2de10b81a 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan WARNING in comedi_unlocked_ioctl
* Struck through repros no longer work on HEAD.