KASAN: stack-out-of-bounds Read in cp2112_xfer

Status: upstream: reported C repro on 2025/11/13 02:45
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+78f74668e7b6e051c055@syzkaller.appspotmail.com
First crash: 255d, last: 186d
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2025/11/22 linux-6.1.y (ToT) f6e38ae624cf C [report] KASAN: stack-out-of-bounds Read in cp2112_xfer
2025/11/22 upstream (ToT) 89edd36fd801 C Didn't crash
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: stack-out-of-bounds Read in cp2112_xfer input 17 C error 8 284d 313d 29/29 fixed on 2025/11/18 08:45
linux-5.15 KASAN: stack-out-of-bounds Read in cp2112_xfer origin:lts-only 17 C error 16 30d 255d 0/3 upstream: reported C repro on 2025/11/13 01:43
linux-6.6 KASAN: stack-out-of-bounds Read in cp2112_xfer origin:lts-only 17 C inconclusive 10 190d 249d 0/2 upstream: reported C repro on 2025/11/19 05:27
▶ ▼ Fix bisection attempts (3)
Created Duration User Patch Repo Result
2026/03/24 15:28 1m fix candidate upstream error job log
2026/02/22 07:36 1m fix candidate upstream error job log
2026/01/23 04:39 1m fix candidate upstream error job log

Sample crash report:
==================================================================
BUG: KASAN: stack-out-of-bounds in cp2112_write_req drivers/hid/hid-cp2112.c:482 [inline]
BUG: KASAN: stack-out-of-bounds in cp2112_xfer+0x60b/0xdd0 drivers/hid/hid-cp2112.c:699
Read of size 42 at addr ffffc90004097d41 by task syz.0.17/4436

CPU: 0 PID: 4436 Comm: syz.0.17 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x22e lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:316 [inline]
 print_report+0xa8/0x210 mm/kasan/report.c:420
 kasan_report+0x10b/0x140 mm/kasan/report.c:524
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x27b/0x290 mm/kasan/generic.c:189
 memcpy+0x25/0x60 mm/kasan/shadow.c:65
 cp2112_write_req drivers/hid/hid-cp2112.c:482 [inline]
 cp2112_xfer+0x60b/0xdd0 drivers/hid/hid-cp2112.c:699
 __i2c_smbus_xfer+0x771/0x1fc0 drivers/i2c/i2c-core-smbus.c:590
 i2c_smbus_xfer+0x263/0x3a0 drivers/i2c/i2c-core-smbus.c:545
 i2cdev_ioctl_smbus+0x3e3/0x650 drivers/i2c/i2c-dev.c:381
 i2cdev_ioctl+0x545/0x750 drivers/i2c/i2c-dev.c:467
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xfa/0x170 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f602e98f6c9
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:00007ffefb4d9468 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f602ebe5fa0 RCX: 00007f602e98f6c9
RDX: 0000200000000200 RSI: 0000000000000720 RDI: 0000000000000004
RBP: 00007f602ea11f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f602ebe5fa0 R14: 00007f602ebe5fa0 R15: 0000000000000003
 </TASK>

The buggy address belongs to stack of task syz.0.17/4436
 and is located at offset 33 in frame:
 i2cdev_ioctl_smbus+0x0/0x650

This frame has 1 object:
 [32, 66) 'temp'

The buggy address belongs to a 8-page vmalloc region starting at 0xffffc90004090000 allocated at copy_process+0x5bd/0x4020 kernel/fork.c:2181
The buggy address belongs to the physical page:
page:ffffea0001efa640 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7be99
memcg:ffff88802fe54f82
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 0000000000000000 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff ffff88802fe54f82
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x102dc2(GFP_HIGHUSER|__GFP_NOWARN|__GFP_ZERO), pid 2, tgid 2 (kthreadd), ts 80965016314, free_ts 66080083383
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x173/0x1a0 mm/page_alloc.c:2532
 prep_new_page mm/page_alloc.c:2539 [inline]
 get_page_from_freelist+0x1a26/0x1ac0 mm/page_alloc.c:4328
 __alloc_pages+0x1df/0x4e0 mm/page_alloc.c:5614
 vm_area_alloc_pages mm/vmalloc.c:3002 [inline]
 __vmalloc_area_node mm/vmalloc.c:3071 [inline]
 __vmalloc_node_range+0x959/0x1390 mm/vmalloc.c:3243
 alloc_thread_stack_node kernel/fork.c:312 [inline]
 dup_task_struct+0x3d3/0x6b0 kernel/fork.c:989
 copy_process+0x5bd/0x4020 kernel/fork.c:2181
 kernel_clone+0x225/0x8b0 kernel/fork.c:2757
 kernel_thread+0xe5/0x140 kernel/fork.c:2817
 create_kthread kernel/kthread.c:399 [inline]
 kthreadd+0x536/0x6e0 kernel/kthread.c:748
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1459 [inline]
 free_pcp_prepare mm/page_alloc.c:1509 [inline]
 free_unref_page_prepare+0x8b4/0x9a0 mm/page_alloc.c:3384
 free_unref_page_list+0xbb/0x8e0 mm/page_alloc.c:3525
 release_pages+0x1f92/0x2200 mm/swap.c:1035
 tlb_batch_pages_flush mm/mmu_gather.c:59 [inline]
 tlb_flush_mmu_free mm/mmu_gather.c:254 [inline]
 tlb_flush_mmu+0xff/0x210 mm/mmu_gather.c:261
 tlb_finish_mmu+0xbd/0x1c0 mm/mmu_gather.c:361
 exit_mmap+0x343/0x8e0 mm/mmap.c:3262
 __mmput+0x118/0x3c0 kernel/fork.c:1200
 exit_mm+0x1e6/0x2c0 kernel/exit.c:565
 do_exit+0x8c1/0x2400 kernel/exit.c:867
 do_group_exit+0x217/0x2d0 kernel/exit.c:1022
 __do_sys_exit_group kernel/exit.c:1033 [inline]
 __se_sys_exit_group kernel/exit.c:1031 [inline]
 __x64_sys_exit_group+0x3b/0x40 kernel/exit.c:1031
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Memory state around the buggy address:
 ffffc90004097c00: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 f3 f3 f3
 ffffc90004097c80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc90004097d00: 00 00 00 00 f1 f1 f1 f1 00 00 00 00 02 f3 f3 f3
                                                       ^
 ffffc90004097d80: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc90004097e00: f1 f1 f1 f1 04 f2 00 00 f2 f2 00 00 f3 f3 f3 f3
==================================================================

Crashes (15):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/11/13 06:50 linux-6.1.y f6e38ae624cf 07e030de .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: stack-out-of-bounds Read in cp2112_xfer
2026/01/16 13:43 linux-6.1.y bec0e10ee67e d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: stack-out-of-bounds Read in cp2112_xfer
2026/01/12 21:48 linux-6.1.y bec0e10ee67e d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: stack-out-of-bounds Read in cp2112_xfer
2026/01/12 21:48 linux-6.1.y bec0e10ee67e d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: stack-out-of-bounds Read in cp2112_xfer
2025/12/29 15:41 linux-6.1.y 50cbba13faa2 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: stack-out-of-bounds Read in cp2112_xfer
2025/12/29 15:40 linux-6.1.y 50cbba13faa2 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: stack-out-of-bounds Read in cp2112_xfer
2025/12/29 01:54 linux-6.1.y 50cbba13faa2 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: stack-out-of-bounds Read in cp2112_xfer
2025/12/29 01:54 linux-6.1.y 50cbba13faa2 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: stack-out-of-bounds Read in cp2112_xfer
2025/12/03 23:29 linux-6.1.y f6e38ae624cf d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: stack-out-of-bounds Read in cp2112_xfer
2025/12/03 23:27 linux-6.1.y f6e38ae624cf d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: stack-out-of-bounds Read in cp2112_xfer
2025/11/13 02:45 linux-6.1.y f6e38ae624cf 07e030de .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan KASAN: stack-out-of-bounds Read in cp2112_xfer
2026/01/20 20:38 linux-6.1.y cd9b81672742 06648d9c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: stack-out-of-bounds Read in cp2112_xfer
2026/01/20 20:36 linux-6.1.y cd9b81672742 06648d9c .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: stack-out-of-bounds Read in cp2112_xfer
2026/01/16 13:28 linux-6.1.y bec0e10ee67e d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: stack-out-of-bounds Read in cp2112_xfer
2025/12/04 11:11 linux-6.1.y f6e38ae624cf d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan-arm64 KASAN: stack-out-of-bounds Read in cp2112_xfer
* Struck through repros no longer work on HEAD.