Forwarded: Re: [syzbot] [input?] KASAN: stack-out-of-bounds Read in cp2112_xfer

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Subject: Re: [syzbot] [input?] KASAN: stack-out-of-bounds Read in cp2112_xfer
Author: deepak.takumi.120@gmail.com

#syz test


On Mon, Sep 15, 2025 at 11:48 PM syzbot
<syzbot+7617e19c8a59edfbd879@syzkaller.appspotmail.com> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    5cd64d4f9268 Merge tag 'ceph-for-6.17-rc6' of https://gith..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=16c0db12580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=4d8792ecb6308d0f
> dashboard link: https://syzkaller.appspot.com/bug?extid=7617e19c8a59edfbd879
> compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=11240762580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1552db62580000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/3840aa3ff580/disk-5cd64d4f.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/aa965f106402/vmlinux-5cd64d4f.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/88839eb3c76c/bzImage-5cd64d4f.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+7617e19c8a59edfbd879@syzkaller.appspotmail.com
>
> ==================================================================
> BUG: KASAN: stack-out-of-bounds in cp2112_write_req drivers/hid/hid-cp2112.c:477 [inline]
> BUG: KASAN: stack-out-of-bounds in cp2112_xfer+0x713/0xf10 drivers/hid/hid-cp2112.c:692
> Read of size 34 at addr ffffc90003c0fd21 by task syz.0.17/6028
>
> CPU: 1 UID: 0 PID: 6028 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
> Call Trace:
>  <TASK>
>  dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
>  print_address_description mm/kasan/report.c:378 [inline]
>  print_report+0xca/0x240 mm/kasan/report.c:482
>  kasan_report+0x118/0x150 mm/kasan/report.c:595
>  check_region_inline mm/kasan/generic.c:-1 [inline]
>  kasan_check_range+0x2b0/0x2c0 mm/kasan/generic.c:189
>  __asan_memcpy+0x29/0x70 mm/kasan/shadow.c:105
>  cp2112_write_req drivers/hid/hid-cp2112.c:477 [inline]
>  cp2112_xfer+0x713/0xf10 drivers/hid/hid-cp2112.c:692
>  __i2c_smbus_xfer+0x5b6/0x1e50 drivers/i2c/i2c-core-smbus.c:591
>  i2c_smbus_xfer+0x275/0x3c0 drivers/i2c/i2c-core-smbus.c:546
>  i2cdev_ioctl_smbus+0x43d/0x6d0 drivers/i2c/i2c-dev.c:389
>  i2cdev_ioctl+0x5d3/0x7f0 drivers/i2c/i2c-dev.c:478
>  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: 0033:0x7f44e378eba9
> 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:00007ffcb2858658 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> RAX: ffffffffffffffda RBX: 00007f44e39d5fa0 RCX: 00007f44e378eba9
> RDX: 0000200000000040 RSI: 0000000000000720 RDI: 0000000000000004
> RBP: 00007f44e3811e19 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007f44e39d5fa0 R14: 00007f44e39d5fa0 R15: 0000000000000003
>  </TASK>
>
> The buggy address belongs to stack of task syz.0.17/6028
>  and is located at offset 33 in frame:
>  i2cdev_ioctl_smbus+0x0/0x6d0 drivers/i2c/i2c-dev.c:317
>
> This frame has 1 object:
>  [32, 66) 'temp'
>
> The buggy address belongs to a vmalloc virtual mapping
> The buggy address belongs to the physical page:
> page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5724d
> memcg:ffff888026b61482
> flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
> raw: 00fff00000000000 0000000000000000 dead000000000122 0000000000000000
> raw: 0000000000000000 0000000000000000 00000001ffffffff ffff888026b61482
> page dumped because: kasan: bad access detected
> page_owner tracks the page as allocated
> page last allocated via order 0, migratetype Unmovable, gfp_mask 0x2dc2(GFP_KERNEL|__GFP_HIGHMEM|__GFP_ZERO|__GFP_NOWARN), pid 5953, tgid 5953 (syz.0.10), ts 82929749894, free_ts 82841187973
>  set_page_owner include/linux/page_owner.h:32 [inline]
>  post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1851
>  prep_new_page mm/page_alloc.c:1859 [inline]
>  get_page_from_freelist+0x21e4/0x22c0 mm/page_alloc.c:3858
>  __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:5148
>  alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2416
>  alloc_frozen_pages_noprof mm/mempolicy.c:2487 [inline]
>  alloc_pages_noprof+0xa9/0x190 mm/mempolicy.c:2507
>  vm_area_alloc_pages mm/vmalloc.c:3642 [inline]
>  __vmalloc_area_node mm/vmalloc.c:3720 [inline]
>  __vmalloc_node_range_noprof+0x97d/0x12f0 mm/vmalloc.c:3893
>  __vmalloc_node_noprof+0xc2/0x110 mm/vmalloc.c:3956
>  alloc_thread_stack_node kernel/fork.c:311 [inline]
>  dup_task_struct+0x3e7/0x860 kernel/fork.c:881
>  copy_process+0x54b/0x3c00 kernel/fork.c:2004
>  kernel_clone+0x21e/0x840 kernel/fork.c:2605
>  __do_sys_clone3 kernel/fork.c:2909 [inline]
>  __se_sys_clone3+0x256/0x2d0 kernel/fork.c:2888
>  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
> page last free pid 5941 tgid 5941 stack trace:
>  reset_page_owner include/linux/page_owner.h:25 [inline]
>  free_pages_prepare mm/page_alloc.c:1395 [inline]
>  __free_frozen_pages+0xbc4/0xd30 mm/page_alloc.c:2895
>  vfree+0x25a/0x400 mm/vmalloc.c:3434
>  kcov_put kernel/kcov.c:439 [inline]
>  kcov_close+0x28/0x50 kernel/kcov.c:535
>  __fput+0x449/0xa70 fs/file_table.c:468
>  task_work_run+0x1d1/0x260 kernel/task_work.c:227
>  exit_task_work include/linux/task_work.h:40 [inline]
>  do_exit+0x6b5/0x2300 kernel/exit.c:961
>  do_group_exit+0x21c/0x2d0 kernel/exit.c:1102
>  get_signal+0x1286/0x1340 kernel/signal.c:3034
>  arch_do_signal_or_restart+0x9a/0x750 arch/x86/kernel/signal.c:337
>  exit_to_user_mode_loop+0x75/0x110 kernel/entry/common.c:40
>  exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
>  syscall_exit_to_user_mode_work include/linux/entry-common.h:175 [inline]
>  syscall_exit_to_user_mode include/linux/entry-common.h:210 [inline]
>  do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
>
> Memory state around the buggy address:
>  ffffc90003c0fc00: 00 00 00 00 f1 f1 f1 f1 00 f3 f3 f3 00 00 00 00
>  ffffc90003c0fc80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> >ffffc90003c0fd00: f1 f1 f1 f1 00 00 00 00 02 f3 f3 f3 f3 f3 f3 f3
>                                            ^
>  ffffc90003c0fd80: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1
>  ffffc90003c0fe00: 04 f2 00 00 f2 f2 00 00 f3 f3 f3 f3 00 00 00 00
> ==================================================================
>
>
> ---
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>
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>
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