syzbot


WARNING in comedi_unlocked_ioctl

Status: upstream: reported C repro on 2025/07/10 11:52
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+4d61e9f9af9f72f89a87@syzkaller.appspotmail.com
First crash: 5d03h, last: 1d14h
Bug presence (1)
Date Name Commit Repro Result
2025/07/14 upstream (ToT) 347e9f5043c8 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 kernel -1 C 168 2h08m 11d 0/29 upstream: reported C repro on 2025/07/04 08:17
linux-6.6 WARNING in comedi_unlocked_ioctl origin:upstream -1 C 4 2d17h 4d11h 0/2 upstream: reported C repro on 2025/07/11 04:26
linux-6.1 WARNING in comedi_unlocked_ioctl origin:upstream -1 C 8 1d21h 4d10h 0/3 upstream: reported C repro on 2025/07/11 04:55

Sample crash report:
------------[ cut here ]------------
WARNING: CPU: 1 PID: 5213 at mm/page_alloc.c:5449 __alloc_pages+0x2b4/0x470 mm/page_alloc.c:5449
Modules linked in:
CPU: 1 PID: 5213 Comm: syz.1.476 Not tainted 5.15.186-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
pstate: 20400005 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : __alloc_pages+0x2b4/0x470 mm/page_alloc.c:5449
lr : __alloc_pages+0xac/0x470 mm/page_alloc.c:5442
sp : ffff800022dd7700
x29: ffff800022dd77d0 x28: 1ffff000035c6cc8 x27: ffff800022dd7720
x26: ffff80001ae36640 x25: dfff800000000000 x24: ffff7000045baee4
x23: ffff80001ae36644 x22: 0000000000000000 x21: 0000000000040dc0
x20: 0000000000000000 x19: 0000000000000019 x18: 0000000000000000
x17: 0000000000000000 x16: ffff800008822af4 x15: 0000000000000005
x14: 0000000000ff0100 x13: ffffffffffffffff x12: 0000000000000005
x11: 1ffff000045baee8 x10: 0000000000000000 x9 : 0000000000000000
x8 : ffff800022dd7768 x7 : 0000000000000000 x6 : ffff800022dd7c40
x5 : ffff800022dd7c40 x4 : 0000000000000000 x3 : 0000000000000020
x2 : 0000000000000008 x1 : 0000000000000000 x0 : ffff800022dd7740
Call trace:
 __alloc_pages+0x2b4/0x470 mm/page_alloc.c:5449
 alloc_pages+0x34c/0x5c0 mm/mempolicy.c:-1
 kmalloc_order+0x40/0x160 mm/slab_common.c:986
 kmalloc_order_trace+0x30/0x244 mm/slab_common.c:1002
 kmalloc_large include/linux/slab.h:533 [inline]
 __kmalloc+0x318/0x44c mm/slub.c:4396
 kmalloc_array include/linux/slab.h:644 [inline]
 kcalloc include/linux/slab.h:673 [inline]
 comedi_unlocked_ioctl+0x914/0xdcc drivers/comedi/comedi_fops.c:2237
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:874 [inline]
 __se_sys_ioctl fs/ioctl.c:860 [inline]
 __arm64_sys_ioctl+0x14c/0x1c8 fs/ioctl.c:860
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x78/0x1e0 arch/arm64/kernel/entry-common.c:608
 el0t_64_sync_handler+0xcc/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584
irq event stamp: 1608
hardirqs last  enabled at (1607): [<ffff80000884efa0>] kasan_quarantine_put+0xc4/0x204 mm/kasan/quarantine.c:231
hardirqs last disabled at (1608): [<ffff8000111cabbc>] el1_dbg+0x24/0x80 arch/arm64/kernel/entry-common.c:396
softirqs last  enabled at (1596): [<ffff80000819e9e8>] softirq_handle_end kernel/softirq.c:419 [inline]
softirqs last  enabled at (1596): [<ffff80000819e9e8>] handle_softirqs+0xa4c/0xbf0 kernel/softirq.c:604
softirqs last disabled at (1569): [<ffff80000819efec>] __do_softirq kernel/softirq.c:610 [inline]
softirqs last disabled at (1569): [<ffff80000819efec>] do_softirq_own_stack include/asm-generic/softirq_stack.h:10 [inline]
softirqs last disabled at (1569): [<ffff80000819efec>] invoke_softirq kernel/softirq.c:457 [inline]
softirqs last disabled at (1569): [<ffff80000819efec>] __irq_exit_rcu+0x240/0x440 kernel/softirq.c:659
---[ end trace 99a4d1b656165b33 ]---

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/10 13:47 linux-5.15.y 3dea0e7f549e 956bd956 .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 WARNING in comedi_unlocked_ioctl
2025/07/12 05:09 linux-5.15.y 2f693b607545 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in comedi_unlocked_ioctl
2025/07/14 00:37 linux-5.15.y 2f693b607545 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 WARNING in comedi_unlocked_ioctl
2025/07/12 06:45 linux-5.15.y 2f693b607545 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 WARNING in comedi_unlocked_ioctl
2025/07/10 11:51 linux-5.15.y 3dea0e7f549e 956bd956 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 WARNING in comedi_unlocked_ioctl
* Struck through repros no longer work on HEAD.