Re: [syzbot] [usb?] WARNING: kobject bug in pch_udc_remove

[Aleksandr Nogikh]

#syz invalid

See the discussion at
https://lore.kernel.org/all/6a88012e.dbb3a75c.13dd47.0007.GAE@xxxxxxxxxx/T/

On Tue, Aug 11, 2026 at 2:53 PM syzbot
<syzbot+3e2e533aa1b2a75525e7@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote:
>
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    d58772d8520c Merge tag 'regmap-fix-v7.2-rc7' of git://git...
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=10996149580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=c44651ea7dd2f307
> dashboard link: https://syzkaller.appspot.com/bug?extid=3e2e533aa1b2a75525e7
> compiler:       gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=17bc2a9e580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17293132580000
>
> Downloadable assets:
> disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-d58772d8.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/caffbd0a7ec1/vmlinux-d58772d8.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/686d959b6f96/bzImage-d58772d8.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+3e2e533aa1b2a75525e7@xxxxxxxxxxxxxxxxxxxxxxxxx
>
> pch_udc 0000:00:03.0: pch_udc_probe: request_irq(23) fail
> ------------[ cut here ]------------
> kobject: '(null)' (ffff888035ce0110): is not initialized, yet kobject_put() is being called.
> WARNING: lib/kobject.c:734 at kobject_put+0x252/0x640 lib/kobject.c:734, CPU#0: syz.0.17/5908
> Modules linked in:
> CPU: 0 UID: 0 PID: 5908 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(full)
> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
> RIP: 0010:kobject_put+0x258/0x640 lib/kobject.c:734
> Code: 59 f6 48 89 da 48 b8 00 00 00 00 00 fc ff df 48 c1 ea 03 80 3c 02 00 0f 85 5e 03 00 00 48 8d 3d de 47 83 05 48 8b 33 48 89 da <67> 48 0f b9 3a e9 0b fe ff ff e8 b9 a8 59 f6 be 03 00 00 00 4c 89
> RSP: 0018:ffffc900035b7918 EFLAGS: 00010246
> RAX: dffffc0000000000 RBX: ffff888035ce0110 RCX: ffffffff8bb0c8c4
> RDX: ffff888035ce0110 RSI: 0000000000000000 RDI: ffffffff91341290
> RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000000 R12: ffff888035ce014c
> R13: dffffc0000000000 R14: ffff888035ce1978 R15: ffff888035ce0608
> FS:  000055558de32500(0000) GS:ffff8880d5dec000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000557c252125d8 CR3: 0000000040736000 CR4: 0000000000352ef0
> Call Trace:
>  <TASK>
>  put_device+0x1f/0x30 drivers/base/core.c:3880
>  pch_udc_remove+0x47/0x510 drivers/usb/gadget/udc/pch_udc.c:2986
>  pch_udc_probe+0xcc6/0x1130 drivers/usb/gadget/udc/pch_udc.c:3109
>  local_pci_probe+0xdd/0x1b0 drivers/pci/pci-driver.c:332
>  pci_call_probe+0x176/0x800 drivers/pci/pci-driver.c:394
>  __pci_device_probe drivers/pci/pci-driver.c:455 [inline]
>  pci_device_probe+0x1cd/0x370 drivers/pci/pci-driver.c:489
>  call_driver_probe drivers/base/dd.c:628 [inline]
>  really_probe+0x241/0xa60 drivers/base/dd.c:706
>  __driver_probe_device+0x20e/0x450 drivers/base/dd.c:868
>  device_driver_attach+0xd1/0x220 drivers/base/dd.c:1203
>  bind_store+0xf4/0x190 drivers/base/bus.c:267
>  drv_attr_store+0x74/0xb0 drivers/base/bus.c:125
>  sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145
>  kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345
>  new_sync_write fs/read_write.c:595 [inline]
>  vfs_write+0x6ac/0x1050 fs/read_write.c:687
>  ksys_write+0x12a/0x250 fs/read_write.c:739
>  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
>  do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7f60b4b9e0d9
> Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007ffdce022f28 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
> RAX: ffffffffffffffda RBX: 00007f60b4e25fa0 RCX: 00007f60b4b9e0d9
> RDX: 000000000000000d RSI: 0000200000000240 RDI: 0000000000000005
> RBP: 00007ffdce022f90 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001
> R13: 00007f60b4e25fac R14: 00007f60b4e25fa0 R15: 00007f60b4e25fa0
>  </TASK>
> ----------------
> Code disassembly (best guess):
>    0:   59                      pop    %rcx
>    1:   f6 48 89 da             testb  $0xda,-0x77(%rax)
>    5:   48 b8 00 00 00 00 00    movabs $0xdffffc0000000000,%rax
>    c:   fc ff df
>    f:   48 c1 ea 03             shr    $0x3,%rdx
>   13:   80 3c 02 00             cmpb   $0x0,(%rdx,%rax,1)
>   17:   0f 85 5e 03 00 00       jne    0x37b
>   1d:   48 8d 3d de 47 83 05    lea    0x58347de(%rip),%rdi        # 0x5834802
>   24:   48 8b 33                mov    (%rbx),%rsi
>   27:   48 89 da                mov    %rbx,%rdx
> * 2a:   67 48 0f b9 3a          ud1    (%edx),%rdi <-- trapping instruction
>   2f:   e9 0b fe ff ff          jmp    0xfffffe3f
>   34:   e8 b9 a8 59 f6          call   0xf659a8f2
>   39:   be 03 00 00 00          mov    $0x3,%esi
>   3e:   4c                      rex.WR
>   3f:   89                      .byte 0x89
>
>
> ---
> This report is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
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>
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>
> If the report is already addressed, let syzbot know by replying with:
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>
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>
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